Semiconductor plating system workpiece support having workpiece engaging electrodes with distal contact part and dielectric cover

ABSTRACT

A semiconductor workpiece holder used in electroplating systems for plating metal layers onto a semiconductor workpieces, and is of particular advantage in connection with plating copper onto semiconductor materials. The workpiece holder includes electrode assemblies which have a contact part which connects to a distal end of an electrode shaft and bears against the workpiece and conducts current therebetween. The contact part is preferably made from a corrosion resistant material, such as platinum. The electrode assembly also preferably includes a dielectric layer which covers the distal end of the electrode shaft and seals against the contact part to prevent plating liquid from corroding the joint between these parts.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of U.S. patent application Ser. No.08/680,057, filed Jul. 15, 1996.

TECHNICAL FIELD

The technical field of this invention is workpiece supports used insemiconductor plating systems having electrodes which engage theworkpieces for electroplating metals, such as copper and others, ontoseed layers formed on semiconductor wafers and other semiconductorworkpieces.

BACKGROUND OF THE INVENTION

In the production of semiconductor wafers and other semiconductorarticles it is necessary to plate metals onto the semiconductor surfaceto provide conductive areas which transfer electrical current. There aretwo primary types of plating layers formed on the wafer or otherworkpiece. One is a blanket layer used to provide a metallic layer whichcovers large areas of the wafer. The other is a patterned layer which isdiscontinuous and provides various localized areas that formelectrically conductive paths within the layer and to adjacent layers ofthe wafer or other device being formed.

The plating of copper onto semiconductor articles has proven to be agreat technical challenge and at this time has not achieved commercialreality due to practical problems of forming copper layers onsemiconductor devices in a reliable and cost efficient manner. This iscaused in part by the relative difficulty in performing reactive ionetching or other selective removal of copper at reasonable productiontemperatures. The selective removal of copper is desirable to formpatterned layers and provide electrically conductive interconnectsbetween adjacent layers of the wafer or other workpiece.

Because reactive ion etching cannot be efficiently used, the industryhas sought to overcome the problem of forming patterned layers of copperby using a damascene process where holes, more commonly called vias,trenches and other recesses are formed in the layer of semiconductormaterial in which the pattern of copper is desired. In the damasceneprocesses the wafer is first provided with a metallic seed layer whichis used to conduct electrical current during a subsequent metalelectroplating step. The seed layer is a very thin layer of metal whichcan be laid down using several processes. The seed layer of metal can belaid down using physical vapor deposition or chemical vapor depositionprocesses to produce a layer on the order of 1000 angstroms thick. Theseed layer can advantageously be formed of copper, gold, nickel,palladium, and most or all other metals. The seed layer is formed over asurface which is convoluted by the presence of vias, trenches, or otherdevice features which are recessed. This convoluted nature of theexposed surface provides increased difficulties in forming the seedlayer in a uniform manner. Nonuniformities in the seed layer can resultin variations in the electrical current passing from the exposed surfaceof the wafer during the subsequent electroplating process. This in turncan lead to nonuniformities in the blanket layer electroplated onto theseed layer. Such nonuniformities can cause deformities and failures inthe resulting semiconductor device being formed.

In the damascene processes, after the seed layer is laid down, then itis typical to plate additional metal onto the seed layer in the form ofa blanket layer formed thereon. The blanket layer is typicallyelectroplated and is used to fill the vias and trenches. The blanketlayer is also typically plated to an extent which forms an overlyinglayer. Such a blanket layer will typically be formed in thicknesses onthe order of 10,000-15,000 angstroms (1-1.5 microns).

The damascene processes also involve the removal of excess metalmaterial present outside of the vias, trenches or other recesses. Themetal is removed to provide a resulting patterned metal layer in thesemiconductor device being formed. The excess plated material can beremoved using chemical mechanical planarization. Chemical mechanicalplanarization is a processing step which uses the combined action of achemical removal agent and an abrasive which remove and polish theexposed surface to remove undesired parts of the metal layer applied inthe electroplating step.

The above process has been found very difficult to perform in a reliableand uniform manner when the electroplating process is performed usingcopper. Thus, the semiconductor industry has not as of this time beenable to efficiently and economically produce semiconductor devices usingcopper metal as the principal conductive material of the device.

These challenges have in the past resulted in the use of aluminum and avariety of aluminum alloys as the metals of choice for formingmetallized layers on semiconductor devices. Aluminum and its alloys havebeen acceptable because they can typically be removed in a defined andselective manner by reactive ion etch technology. This ion etchproduction technology uses a patterned photoresist layer which acts as ashield or stencil covering portions of an aluminum or alloy blanketlayer which are to remain.

Despite the greater manufacturing ease, the performance of semiconductordevices can be significantly enhanced by using copper since copper issignificantly more conductive than aluminum. The frequent use ofaluminum alloys further emphasizes the advantages of copper because thealloying introduces additional constituents to the matrix of thealuminum which further increases resistivity and decreases conductivity.Copper provides for more efficient and faster conduction of electricalsignals within the semiconductor devices.

Another problem faced in the plating of metals onto semiconductorarticles is the destruction of the seed layer at or near the place ofcontact by the electrodes. The contacting electrodes produce localizedcurrent densities which are frequently high due to the very thin natureof the seed layer. Localized areas having excessive current densitiescan lead to nonuniformities in the layer being plated.

The chemical composition of the plating bath liquid also typicallyincludes acid components which are a contributing factor in corrosionwhich can occur at or about the point of electrode contact. Corrosionalso can develop on and about the electrode contact which can exacerbatethe problems of uniformity and excessive localized current densitylevels.

Circulation of the plating bath liquid is typically done in order tomaintain chemical uniformity and allow makeup of consumed components ofthe plating liquid. This circulation may also contribute to seed layerdestruction in some situations. These concerns are of particularsignificance in the plating of copper onto semiconductor wafers.

Thus, there is a continuing need in the art for improved semiconductorplating systems which can plate copper and other layers ontosemiconductor articles in a manner which is uniform and which can bedone in an efficient and cost-effective manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the accompanying drawings, which are briefly describedbelow.

FIG. 1 is an environmental view of the semiconductor processing head ofthe present invention showing two processing heads in a processingstation, one in a deployed, "closed" or "processing" position, and onein an "open" or "receive wafer" position.

FIG. 2 is an isometric view of the semiconductor processing head of thepresent invention.

FIG. 3 is a side elevation view of the processing head of the presentinvention showing the head in a "receive wafer" position.

FIG. 4 is a side elevation view of the processing head of FIG. 6 showingthe head in a rotated position ready to lower the wafer into theprocessing station.

FIG. 5 is a side elevation view of the processing head of FIG. 6 showingthe head operator pivoted to deploy the processing head and wafer intothe bowl of the processing station.

FIG. 6 is a schematic front elevation view of the processing headindicating the portions detailed in FIGS. 7 and 8.

FIG. 7 is a front elevation sectional view of the left half of theprocessing head of the apparatus of the present invention also showing afirst embodiment of the wafer holding fingers.

FIG. 8 is a front elevation sectional view of the left half of theprocessing head of the apparatus of the present invention also showing afirst embodiment of the wafer holding fingers.

FIG. 9 is an isometric view of the operator base and operator arm of theapparatus of the present invention with the protective cover removed.

FIG. 10 is a right side elevation view of the operator arm of thepresent invention showing the processing head pivot drive mechanism.

FIG. 11 is a left side elevation view of the operator arm of the presentinvention showing the operator arm drive mechanism.

FIG. 12 is schematic plan view of the operator arm indicating theportions detailed in FIGS. 13 and 14.

FIG. 13 is a partial sectional plan view of the right side of theoperator arm showing the processing head drive mechanism.

FIG. 14 is a partial sectional plan view of the left side of theoperator arm showing the operator arm drive mechanism.

FIG. 15 is a side elevational view of a semiconductor workpiece holderconstructed according to a preferred aspect of the invention.

FIG. 16 is a front sectional view of the FIG. 1 semiconductor workpieceholder.

FIG. 17 is a top plan view of a rotor which is constructed in accordancewith a preferred aspect of this invention, and which is taken along line3--3 in FIG. 16.

FIG. 18 is an isolated side sectional view of a finger assemblyconstructed in accordance with a preferred aspect of the invention andwhich is configured for mounting upon the FIG. 17 rotor.

FIG. 19 is a side elevational view of the finger assembly of FIG. 18.

FIG. 20 is a fragmentary cross-sectional enlarged view of a fingerassembly and associated rotor structure.

FIG. 21 is a view taken along line 7--7 in FIG. 4 and shows a portion ofthe preferred finger assembly moving between an engaged and disengagedposition.

FIG. 22 is a view of a finger tip of the preferred finger assembly andshows an electrode tip in a retracted or disengaged position (solidlines) and an engaged position (phantom lines) against a semiconductorworkpiece.

FIG. 23 is a sectional view showing a second embodiment semiconductorprocessing station having a workpiece support assembly and a platingstation bowl assembly.

FIG. 24 is an enlarged sectional view similar to FIG. 23 showing onlyportions of the workpiece support.

FIG. 25 is an exploded perspective view of portions of the workpiecesupport shown in FIG. 24.

FIG. 26 is an exploded perspective view of portions of a rotor assemblyforming part of the workpiece support shown in FIG. 24.

FIG. 27 is a perspective view showing an interior face of the rotorassembly.

FIG. 28 is a perspective view showing the interior face of the rotorassembly with a wafer supported thereon.

FIG. 29 is an enlarged perspective view showing an actuator transmissionwhich mounts on the rotor assembly and controls motion ofworkpiece-engaging fingers.

FIG. 30 is an exploded perspective assembly view of the actuatortransmission shown in FIG. 29.

FIG. 31 is a longitudinal sectional view of the actuator transmissionshown in FIG. 29.

FIG. 32 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 33 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 34 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 35 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 36 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 37 is a sectional view showing an enlarged distal tip portion of afurther electrode before being pre-conditioned in accordance withanother aspect of the invention.

FIG. 38 is a sectional view showing the enlarge distal tip portion ofthe previous figure after being pre-conditioned.

FIG. 39 is a longitudinal sectional view of one preferred form ofelectrode assembly which can be used in the second embodiment processingsystem.

FIG. 40 is a sectional view showing the electrode assembly of FIG. 39 inposition ready to engage a semiconductor workpiece.

FIG. 41 is a sectional view showing the electrode assembly of FIG. 39 inan engaged position with a semiconductor workpiece.

FIG. 42 is a longitudinal sectional view showing the plating stationbowl shown in FIG. 23.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws "to promote the progressof science and useful arts" (Article 1, Section 8).

                                      TABLE 1                                     __________________________________________________________________________    Listing of Subsections of Detailed Description and                            Pertinent Items with Reference Numerals and Page Numbers                      __________________________________________________________________________    Workpiece Support 14                                                                              process pivot axis 411                                                                          14                                      semiconductor processing machine 400                                                            14                                                                              operator pivot axis 412                                                                         15                                      workpiece supports 401                                                                          14                                                                              workpiece W       15                                      Workpiece support 402                                                                           14                                                                              fingertips 414    15                                      Workpiece support 403                                                                           14                                                                              processing bowl 417                                                                             15                                      semiconductor manufacturing chamber                                                               left and right forks 418 and 419                                                                16                                      404               14                                                          beam emitter 81   14                                                                              Operator Base     17                                      operator base 405 14                                                                              operator base back portion 420                                                                  17                                      processing head 406                                                                             14                                                                              operator base left yoke arm 421                                                                 17                                      operator arm 407  14                                                                              operator base right yoke arm 422                                                                17                                      wafer holder 408  14                                                                              yoke arm fasteners 423                                                                          17                                      fingers 409       14                                                                              operator arm bearings 424                                                                       17                                      Workpiece holder 408                                                                            14                                                                              operator arm 425  17                                      workpiece spin axis 410                                                                         14                                                          Operator Arm      17                                                                              Processing Head Spin Motor                                                                      28                                      process arm rear cavity 426                                                                     18                                                                              workpiece holder 478                                                                            28                                      lift motor 452    18                                                                              spin axis 479     28                                      rotate motor 428  18                                                                              spin motor 480    29                                      processing head left pivot shaft                                                                18                                                                              top motor housing 481                                                                           29                                      processing head right pivot shaft 430                                                           18                                                                              spin motor shaft 483                                                                            29                                                          workpiece holder rotor 484                                                                      29                                      Operator Arm-Processing Head Rotate                                                               rotor hub 485     29                                      Mechanism         18                                                                              rotor hub recess 486                                                                            29                                      Processing head rotate mechanism 431                                                            19                                                                              workpiece shaft snap-ring 488                                                                   29                                      rotate shaft 432  19                                                                              rotor recess groove 489                                                                         29                                      securing collar 433                                                                             19                                                                              spin encoder 498  30                                      rotate motor support 434                                                                        19                                                                              optical tachometer 499                                                                          30                                      rotate encoder 435                                                                              19                                                          rotate pulley inboard bearing 436                                                               20                                                                              Processing Head Finger Actuators                                                                32                                      rotate belt 437   20                                                                              Pneumatic piston 502                                                                            33                                      processing head pulley 438                                                                      20                                                                              actuator spring 505                                                                             33                                      rotate belt tensioner 439                                                                       21                                                                              cavity end cap 507                                                                              33                                      tensioner hub 468 21                                                                              retaining ring 508                                                                              33                                      processing head shaft bearing 440                                                               21                                                                              pneumatic inlet 503                                                                             33                                      processing head rotate bearing 469                                                              21                                                                              pneumatic supply line 504                                                                       33                                      processing head shaft bearing 441                                                               21                                                                              actuator plate 509                                                                              33                                      cable brackets 442 and 443                                                                      22                                                                              actuator plate connect screw 501                                                                33                                      rotate overtravel protect 444                                                                   22                                                                              Wave springs 529  33                                      rotate flag 447   23                                                                              bushing 512       33                                      Rotate optical switches 445 and 446                                                             23                                                                              pneumatic piston recess 511                                                                     33                                                          finger actuator contacts 513                                                                    34                                      Operator Arm-Lift Mechanism                                                                     23                                                          operator arrn lift mechanism 448                                                                23                                                                              Processing Head Workpiece Holder                                                                34                                      lift motor shaft 454                                                                            24                                                                              finger actuator lever 514                                                                       34                                      lift gear drive 453                                                                             24                                                                              finger stem 515   35                                      lift drive shaft 456                                                                            24                                                                              finger diaphragm 519                                                                            35                                      lift bushing 449  24                                                                              workpiece holder rotor 484                                                                      35                                      anchor plate 458  24                                                                              finger opening 521                                                                              35                                      anchor fasteners 457                                                                            24                                                                              rotor diaphragm 523                                                                             35                                      Lift bearing 450  24                                                                              finger spring 520 35                                      lift bearing support 460                                                                        25                                                                              finger actuator tab 522                                                                         35                                      operator arm frame 461                                                                          25                                                                              finger collar or nut 517                                                                        35                                      lift anchor 451   25                                                                              shoulder 518      35                                      lift overtravel protect 462                                                                     25                                                                              finger actuator mechanism 500                                                                   36                                      lift optical switch low 463                                                                     26                                                                              cavity 501        36                                      lift optical switch high 464                                                                    26                                                          lift flag 465     26                                                                              Semiconductor Workpiece Holder-                           lift motor encoder 455                                                                          26                                                                              Electroplating Embodiment                                                                       36                                      lift motor 452    26                                                                              semiconductor workpiece holder 810                                                              36                                      slotted lift flag mounting slots 467                                                            26                                                                              bottom half or bowl 811                                                                         37                                      lift flag fasteners 466                                                                         26                                                                              Processing Head and Processing Head                       Processing Head   27                                                                              Operator          37                                      processing head housing 470                                                                     27                                                                              workpiece support 812                                                                           37                                      circumferential grooves 471                                                                     27                                                                              spin head assembly 814                                                                          37                                      rotate shaft openings 474 and 475                                                               27                                                                              lift/rotate assembly 816                                                                        37                                      left and right processing head mounts                                                             motor 818         38                                      472               27                                                                              rotor 820         38                                      processing head door 476                                                                        27                                                                              rotor spin axis 822                                                                             38                                      processing head void 477                                                                        28                                                                              finger assembly 824                                                                             39                                      actuator 825      39                                                                              rotor assembly 984                                                                              56                                      rotor center piece 826                                                                          39                                                          spokes 828        39                                                                              Workpiece Support Head Operator                                                                 56                                      rotor perimeter piece 830                                                                       39                                                                              processing head 906                                                                             56                                                          head operator 907 56                                      Finger Assembly   40                                                                              upper portion 908 56                                      finger assembly frame 832                                                                       41                                                                              head connection shaft 909                                                                       56                                      angled slot 832a  41                                                                              horizontal pivot axis 910                                                                       56                                      finger assembly frame outer flange 834                                                          41                                                          inner drive plate portion 836                                                                   41                                                                              Workpiece Support Main Part                                                                     57                                                          processing head housing 970                                                                     57                                      Finger Assembly Drive System                                                                    41                                                                              processing head frame 982                                                                       57                                      bearing 838       42                                                                              door plate 983    57                                      collet 840        42                                                                              door ring member 984                                                                            57                                      bearing receptacle 839                                                                          42                                                                              frame-pivot shaft connection 985                                                                57                                      spring 842        42                                                                              pivot shaft connection base 935                                                                 58                                      spring seat 844   42                                                                              first housing part 971                                                                          58                                                          housing cap 972   58                                      Finger Assembly Electrical System                                                               43                                                                              main part mechanism chamber 973                                                                 58                                      pin connector 846 43                                                                              peripheral groove 986                                                                           58                                      finger 848        43                                                                              inflatable door seal 987                                                                        58                                      nut 850           43                                                                              annular rotor receiving groove 988                                                              58                                      anti-rotation pin 852                                                                           43                                                          finger tip 854    44                                                                              Workpiece Support Rotor Drive                                                                   59                                      electrode contact 858                                                                           44                                                                              workpiece spin motor 980                                                                        59                                                          stator armatures 916                                                                            59                                      Finger Assembly Drive System Interface                                                          44                                                                              motor shaft 918   59                                      finger actuator 862                                                                             44                                                                              bottom motor bearing 921                                                                        59                                      actuation ring 863                                                                              45                                                                              bottom motor housing 922                                                                        59                                      first movement path axis 864                                                                    45                                                                              top motor housing 923                                                                           59                                      secondary linkage 865                                                                           45                                                                              top motor bearing 927                                                                           59                                      link arm 867      45                                                                              fasteners 924     60                                      actuator torque ring 869                                                                        45                                                                              frame extensions 925                                                                            60                                      pneumatic operator 871                                                                          45                                                                              top frame piece 926                                                                             60                                      Engaged and Disengaged Positions                                                                46                                                                              Workpiece Support Rotor Assembly                                                                60                                      arrow A           47                                                                              rotor assembly 930                                                                              60                                      workpiece standoff 865                                                                          47                                                                              rotor shaft 931   60                                      bend 866          48                                                                              rotor shaft hub 932                                                                             60                                                          shaft hub receptacle 933                                                                        60                                      Finger Assembly Seal                                                                            48                                                                              inner rotor part 934                                                                            60                                      seal 868          48                                                                              inner rotor part hub 935                                                                        60                                      rim portion 870   48                                                                              peripheral band 936                                                                             60                                                          snap-ring 937     60                                      Methods and Operation                                                                           50                                                                              transmission receptacles 937                                                                    60                                                          fasteners 941     61                                      Second Embodiment Processing Station-                                                             rotor face panel 943                                                                            61                                      Generally         55                                                                              apertures 787     61                                      second semiconductor processing station                                                           support standoffs 721                                                                           61                                      900               55                                                                              workpiece peripheral guide pins 722                                                             61                                      workpiece support assembly 901                                                                  56                                                                              reinforcing ribs 942                                                                            61                                      processing bowl 917                                                                             56                                                                              side wall 944     61                                      processing or manufacturing chamber                                                               finger passageways 949                                                                          62                                      904               56                                                                              rotor shaft mounting nut 888                                                                    62                                                          angular position encoder 498                                                                    62                                      Workpiece Support Generally                                                                     56                                                          Workpiece Detection Subsystem                                                                   63                                                                              dielectric sheath 621                                                                           73                                      mounting 738      64                                                          detector 739      64                                                                              Electrode Fingers With Dielectric Sheaths                 workpiece detector windows 741                                                                  64                                                                              Covering Submerged Areas                                                                        75                                                          electrode finger 681                                                                            75                                      Workpiece Support Finger Actuator                                                               66                                                                              dielectric sheath 682                                                                           75                                      finger pivot axes 953                                                                           66                                                                              contact insert side walls 619                                                                   75                                      workpiece standoff supports 721                                                                 66                                                                              insert contact part or tip 655                                                                  75                                      finger actuator transmission 960                                                                67                                                          finger head mounting receptacle 954                                                             67                                                                              Pre-Conditioning of Electrode Contact                     locking pin groove 955                                                                          67                                                                              Faces             76                                      finger mounting pin 956                                                                         67                                                                              electrode 614     76                                      transmission base 961                                                                           67                                                                              distal exposed surface 615                                                                      76                                      mounting cutout 962                                                                             67                                                                              dielectric sheath 616                                                                           77                                      transmission shaft 963                                                                          68                                                          shaft channel or groove 964                                                                     68                                                                              Methods Using Workpiece-Engaging                          shaft camming control member                                                                    68                                                                              Electrode Assembly With Sealing Boot                                                            78                                      ball 966          68                                                                              electrode finger 583                                                                            78                                      ball support fastener 967                                                                       68                                                                              electrode shaft 584                                                                             78                                      interior shaft passageway 968                                                                   68                                                                              head 633          78                                      spring retainer 969                                                                             68                                                                              cover or boot 585 78                                      finger mounting spring 938                                                                      68                                                                              distal contact lip 586                                                                          79                                      set screw 939     69                                                                              contact insert part 655                                                                         79                                      transmision head 656                                                                            69                                                                              skirt portion 587 79                                      bearing 657       69                                                                              electrode shaft distal end surface 588                                                          79                                      head pieces 658 and 659                                                                         69                                                                              contact face 617  79                                      head fasteners 660                                                                              69                                                                              substrate or other subjacent layer 561                                                          79                                      head guide rods 661                                                                             69                                                                              thin metallic seed layer 562                                                                    79                                      two guide passageways 662                                                                       69                                                                              via or other opening 563                                                                        79                                      head bias springs 664                                                                           69                                                                              photoresist layer 564                                                                           79                                      shaft seal 667    69                                                          transmission head depression ring 683                                                           69                                                                              Plating Bowl Assembly                                                                           82                                      operator output connection ring 684                                                             69                                                                              electroplating bowl assembly 303                                                                82                                      pneumatic actuator engines 691                                                                  70                                                                              process bowl or plating vessel 316                                                              82                                      pneumatic manifolds 692                                                                         70                                                                              outer bowl side wall 617                                                                        82                                                          bowl bottom 319   82                                      Electrode Fingers With Submerged                                                                  bowl rim assembly 314                                                                           82                                      Conductive Current Transfer Areas                                                               70                                                                              cup assembly 320  82                                      finger assembly 631                                                                             70                                                                              fluid cup portion 321                                                                           82                                      finger shaft 632  70                                                                              cup side 322      82                                      finger head 633   70                                                                              cup bottom 323    82                                      locking pin 956   70                                                                              flutes 372        82                                      dielectric sheathing 634 and 635                                                                71                                                                              cup main joint 387                                                                              83                                      contact head 636  71                                                                              riser tube 361    83                                      contact face 637  71                                                                              fitting 362       83                                      submersion line 639                                                                             71                                                                              fluid inlet line 325                                                                            83                                      first electrically conductive segment 642                                                       71                                                                              bowl bottom opening 327                                                                         83                                      second electrically conductive segment                                                            cup fluid inlet openings 324                                                                    83                                      643               71                                                                              overflow chamber 345                                                                            83                                      third electrically conductive segment 644                                                       72                                                                              level detectors 351 and 352                                                                     84                                      third dielectric segment 653                                                                    72                                                                              diffuser height adjustment mechanisms                     third dielectric sheath 654                                                                     72                                                                              386               85                                      distal contact insert part 655                                                                  73                                                                              mounting fasteners 389                                                                          85                                      insert receptacle 616                                                                           73                                                          contact face 617  73                                                                              Plating Anode Shield                                                                            85                                      electrode finger 979                                                                            73                                                                              anode shield 393  85                                      anode shield fasteners 394                                                                      85                                                          * * * (End of Table 1) * * *                                                  __________________________________________________________________________

Workpiece Support

Turning now to FIG. 1, a semiconductor processing machine 400 having twoworkpiece supports 401 is shown. Workpiece support 402 is shown in a"open" or "receive wafer" position in order to receive a workpiece orsemiconductor wafer for further processing. Workpiece support 403 isshown in a "closed" or "deployed" position wherein the semiconductorwafer has been received by the workpiece support and is being exposed tothe semiconductor manufacturing process in the semiconductormanufacturing chamber 404. FIG. 1 also shows an optional beam emitter 81for emitting a laser beam detected by robotic wafer conveyors toindicate position of the unit.

Turning now to FIG. 2, an enlarged view of the workpiece support 401 isshown. Workpiece support 401 advantageously includes operator base 405,a processing head 406, and an operator arm 407. Processing head 406preferably includes workpiece holder or wafer holder 408 and whichfurther includes fingers 409 for securely holding the workpiece duringfurther process and manufacturing steps. Workpiece holder 408 morepreferably spins about workpiece spin axis 410.

The processing head is advantageously rotatable about processing headpivot axis or, more briefly termed, process pivot axis 411. In thismanner, a workpiece (not shown) may be disposed between and grasped bythe fingers 409, at which point the processing head is preferablyrotated about process head pivot axis 411 to place the workpiece in aposition to be exposed to the manufacturing process.

In the preferred embodiment, operator arm 407 may be pivoted aboutoperator pivot axis 412. In this manner, the workpiece is advantageouslylowered into the process bowl (not shown) to accomplish a step in themanufacture of the semiconductor wafer.

Turning now to FIGS. 3-5, the sequence of placing a workpiece on theworkpiece support and exposing the workpiece to the semiconductormanufacturing process is shown. In FIG. 3, a workpiece W is shown asbeing held in place by fingertips 414 of fingers 409. Workpiece W isgrasped by fingertips 414 after being placed in position by robot orother means.

Once the workpiece W has been securely engaged by fingertips 414,processing head 406 can be rotated about process head pivot axis 411 asshown in FIG. 4. Process head 406 is preferably rotated about axis 411until workpiece W is at a desired angle, such as approximatelyhorizontal. The operator arm 407 is pivoted about operator arm pivotaxis 412 in a manner so as to coordinate the angular position ofprocessing head 406. In the closed position, the processing head isplaced against the rim of bowl 416 and the workpiece W is essentially ina horizontal plane. Once the workpiece W has been secured in thisposition, any of a series of various semiconductor manufacturing processsteps may be applied to the workpiece as it is exposed in the processingbowl 417.

Since the processing head 406 is engaged by the operator arm 407 on theleft and right side by the preferably horizontal axis 411 connecting thepivot points of processing head 406, a high degree of stability aboutthe horizontal plane is obtained. Further, since the operator arm 407 islikewise connected to the operator base 405 at left and right sidesalong the essentially horizontal line 412 connecting the pivot points ofthe operator arm, the workpiece support forms a structure having highrigidity in the horizontal plane parallel to and defined by axes 411 and412. Finally, since operator base 405 is securely attached to thesemiconductor process machine 400, rigidity about the spin axis 410 isalso achieved.

Similarly, since processing head 406 is nested within the fork or yokeshaped operator arm 407 having left and right forks 418 and 419,respectively, as shown in FIG. 2, motion due to cantilevering of theprocessing head is reduced as a result of the reduced moment arm definedby the line connecting pivot axes 411 and 412.

In a typical semiconductor manufacturing process, the workpiece holder408 will rotate the workpiece, having the process head 406 secured attwo points, that is, at the left and right forks 418 and 419,respectively, the vibration induced by the rotation of the workpieceholder 408 will be significantly reduced along the axis 411.

A more complete description of the components of the present inventionand their operation and interrelation follows.

Operator Base

Turning now to FIG. 9, operator base 405 is shown. The present inventionadvantageously includes an operator base 405 which forms an essentiallyyoke-shaped base having an operator base back portion 420, an operatorbase left yoke arm 421, and an operator base right yoke arm 422. Yokearms 421 and 422 are securely connected to the base of the yoke 420. Inthe preferred embodiment, the yoke arms are secured to the yoke base bythe yoke arm fasteners 423. The yoke arm base in turn is advantageouslyconnected to the semiconductor process machine 400 as shown in FIG. 1.

The upper portions of the yoke arm advantageously include receptaclesfor housing the operator arm bearings 424 which are used to support thepivot shafts of the operator arm 425, described more fully below.

Operator Arm

Still viewing FIG. 9, the present invention advantageously includes anoperator arm 407. As described previously, operator arm 407 preferablypivots about the operator arm pivot axis 412 which connects the centerline defined by the centers of operator arm pivot bearings 424.

Operator arm or pivot arm 407 is advantageously constructed in such amanner to reduce mass cantilevered about operator arm pivot axis 412.This allows for quicker and more accurate positioning of the pivot armas it is moved about pivot arm axis 412.

The left fork of the pivot arm 418, shown more clearly in FIG. 11,houses the mechanism for causing the pivot arm to lift or rotate aboutpivot arm pivot axis 412. Pivot arm right fork 419, shown more clearlyin FIG. 10, houses the mechanism for causing the processing head 406(not shown) to rotate about the process head pivot axis 411.

The process arm rear cavity 426, shown in FIG. 9, houses the lift motor452 for causing the operator arm 407 to rotate about pivot arm axis 412.Process arm rear cavity 426 also houses rotate motor 428 which is usedto cause the processing head 406 to rotate about the processing headpivot axis 411. The rotate motor 428 may more generally be described asa processing head pivot or rotate drive. Processing head 406 is mountedto operator arm 407 at processing head left pivot shaft 429 andprocessing head right pivot shaft 430.

Operator arm 407 is securely attached to left yoke arm 421 and rightyoke arm 422 by operator arm pivot shafts 425 and operator arm pivotbearings 424, the right of which such bearing shaft and bearings areshown in FIG. 9.

Operator Arm-Processing Head Rotate Mechanism

Turning now to FIG. 13, a sectional plan view of the right rear cornerof operator arm 407 is shown. The right rear section of operator arm 407advantageously contains the rotate mechanism which is used to rotateprocessing head 406 about processing head pivot shafts 430 and 429.Processing head rotate mechanism 431 preferably consists of rotate motor428 which drives rotate shaft 432, more generally described as aprocessing head drive shaft. Rotate shaft 432 is inserted within rotatepulley 425 which also functions as the operator arm pivot shaft. Asdescribed previously, the operator arm pivot shaft/lift pulley issupported in operator arm pivot bearings 424, which are themselvessupported in operator base yoke arm 422. Rotate shaft 432 is securedwithin left pulley 424 by securing collar 433. Securing collar 433secures rotate pulley 425 to rotate shaft 432 in a secure manner so asto assure a positive connection between rotate motor 428 and rotatepulley 425. An inner cover 584 is also provided.

Rotate motor 428 is disposed within process arm rear cavity 426 and issupported by rotate motor support 434. Rotate motor 428 preferably is aservo allowing for accurate control of speed and acceleration of themotor. Servo motor 428 is advantageously connected to rotate encoder 435which is positioned on one end of rotate motor 428. Rotate encoder 435,more generally described as a processing head encoder, allows foraccurate measurement of the number of rotations of rotate motor 428, aswell as the position, speed, and acceleration of the rotate shaft 432.The information from the rotate encoder may be used in a rotate circuitwhich may then be used to control the rotate motor when the rotate motoris a servo. This information is useful in obtaining the position andrate of travel of the processing head, as well as controlling the finalend point positions of the processing head as it is rotated aboutprocess head rotate axis 411.

The relationship between the rotate motor rotations, as measured byrotate encoder 435, may easily be determined once the diameters of therotate pulley 425 and the processing head pulley 438 are known. Thesediameters can be used to determine the ratio of rotate motor relationsto processing head rotations. This may be accomplished by amicroprocessor, as well as other means.

Rotate pulley 425 is further supported within operator arm 407 by rotatepulley inboard bearing 436 which is disposed about an extended flange onthe rotate pulley 425. Rotate pulley inboard bearing 436 is secured bythe body of the operator arm 407, as shown in FIG. 13.

Rotate pulley 425 advantageously drives rotate belt 437, more generallydescribed as a flexible power transmission coupling. Referring now toFIG. 10, rotate belt 437 is shown in the side view of the right arm 419of the operator arm 407. Rotate belt 437 is preferably a toothed timingbelt to ensure positive engagement with the processing head drive wheel,more particularly described herein as the processing head pulley 438,(not shown in this view). In order to accommodate the toothed timingbelt 437, both the rotate pulley 425 and the processing head pulley 438are advantageously provided with gear teeth to match the tooth patternof the timing belt to assure positive engagement of the pulleys with therotate belt.

Rotate mechanism 431 is preferably provided with rotate belt tensioner439, useful for adjusting the belt to take up slack as the belt maystretch during use, and to allow for adjustment of the belt to assurepositive engagement with both the rotate pulley and the processing headpulley. Rotate belt tensioner 439 adjusts the tension of rotate belt 437by increasing the length of the belt path between rotate pulley 425 andprocessing head pulley 438, thereby accommodating any excess length inthe belt. Inversely, the length of the belt path may also be shortenedby adjusting rotate belt tensioner 439 so as to create a more linearpath in the upper portion of rotate belt 437. The tensioner 439 isadjusted by rotating it about tensioner hub 468 and securing it in a newposition.

Turning now to FIG. 13, processing head pulley 438 is mounted toprocessing head rotate shaft 430 in a secured manner so that rotation ofprocessing head pulley 438 will cause processing head rotate shaft 430to rotate. Processing head shaft 430 is mounted to operator arm rightfork 419 by processing head shaft bearing 440, which in turn is securedin the frame of the right fork 419 by processing head rotate bearing469. In a like manner, processing head shaft 429 is mounted in operatorarm left fork 418 by processing head shaft bearing 441, as shown in FIG.9.

Processing head pivot shafts 430 and 429 are advantageously hollowshafts. This feature is useful in allowing electrical, optical,pneumatic, and other signal and supply services to be provided to theprocessing head. Service lines such as those just described which arerouted through the hollow portions of processing head pivot shafts 429and 430 are held in place in the operator arms by cable brackets 442 and443. Cable brackets 442 and 443 serve a dual purpose. First, routing theservice lines away from operating components within the operator armleft and right forks. Second, cable brackets 442 and 443 serve a usefulfunction in isolating forces imparted to the service cables by therotating action of processing head 406 as it rotates about processinghead pivot shafts 429 and 430. This rotating of the processing head 406has the consequence that the service cables are twisted within the pivotshafts as a result of the rotation, thereby imparting forces to thecables. These forces are preferably isolated to a particular area so asto minimize the effects of the forces on the cables. The cable brackets442 and 443 achieve this isolating effect.

The process head rotate mechanism 431, shown in FIG. 13, is alsoadvantageously provided with a rotate overtravel protect 444, whichfunctions as a rotate switch. Rotate overtravel protect 444 preferablyacts as a secondary system to the rotate encoder 435 should the controlsystem fail for some reason to stop servo 428 in accordance with apredetermined position, as would be established by rotate encoder 435.Turning to FIG. 13, the rotate overtravel protect 444 is shown in planview. The rotate overtravel protect preferably consists of rotateoptical switches 445 and 446, which are configured to correspond to theextreme (beginning and end point) portions of the processing head, aswell as the primary switch component which preferably is a rotate flag447. Rotate flag 447 is securely attached to processing head pulley 438such that when processing head shaft 430 (and consequently processinghead 406) are rotated by virtue of drive forces imparted to theprocessing head pulley 425 by the rotate belt 437, the rotate flag 447will rotate thereby tracking the rotate motion of processing head 406.Rotate optical switches 445 and 446 are positioned such that rotate flag447 may pass within the optical path generated by each optical switch,thereby generating a switch signal. The switch signal is used to controlan event such as stopping rotate motor 428. Rotate optical switch 445will guard against overtravel of processing head 406 in one direction,while rotate optical switch 446 will provide against overtravel of theprocessing head 406 in the opposite direction.

Operator Arm-Lift Mechanism

Operator arm 407 is also advantageously provided with an operator armlift mechanism 448 which is useful for causing the operator arm to lift,that is, to pivot or rotate about operator arm pivot axis 412. Turningto FIG. 14, the operator arm lift mechanism 448 is shown in thesectional plan view of the right rear corner of operator arm 407.

Operator arm lift mechanism 448 is advantageously driven by lift motor452. Lift motor 452 may be more generally described as an operator armdrive or operator arm pivot drive. Lift motor 452 is preferably a servomotor and is more preferably provided with an operator encoder, morespecifically described as lift motor encoder 456. When lift motor 452 isa servo motor coupled with lift encoder 456, information regarding thespeed and absolute rotational position of the lift motor shaft 454 maybe known from the lift encoder signal. Additionally, by virtue of beinga servo mechanism, the angular speed and acceleration of lift motor 452may be easily controlled by use of the lift signal by an electricalcircuit. Such a lift circuit may be configured to generate desired liftcharacteristics (speed, angle, acceleration, etc.). FIG. 14 shows thatthe lift operator may also include a brake 455 which is used to safelystop the arm if power fails.

Lift motor 452 drives lift motor shaft 454 which in turn drives liftgear drive 453. Lift gear drive 453 is a gear reduction drive to producea reduced number of revolutions at lift drive shaft 456 as the functionof input revolutions from lift motor shaft 454.

Lift drive gear shaft 456 is secured to lift anchor 451 which is moreclearly shown in FIG. 11. Lift anchor 451 is preferably shaped to haveat least one flat side for positively engaging lift bushing 449. Liftanchor 451 is secured to lift drive shaft 456 by anchor plate 458 andanchor fasteners 457. In this manner, when lift drive shaft 456 isrotated, it will positively engage lift bushing 449. Returning to FIG.14, it is seen that lift bushing 449 is mounted in operator left yokearm 421, and is thus fixed with respect to operator base 405. Liftbearing 450 is disposed about the lift bushing shank and is supported inoperator arm 407 by lift bearing support 460 which is a bushingconfigured to receive lift bearing 450 on a first end and to supportlift gear drive 453 on a second end. Lift bearing support 460 is furthersupported within operator arm 407 by operator arm frame 461. The liftarm is thus free to pivot about lift bushing 449 by virtue of liftbearing 450.

In operation, as lift motor 452 causes lift gear drive 453 to producerotations at gear drive shaft 456, lift anchor 451 is forced againstlift bushing 449 which is securely positioned within right operator yokearm 421. The reactive force against the lift anchor 451 will cause liftbearing support 460 to rotate relative to lift bushing 449. Since liftbushing 449 is fixed in operator base 405, and since operator base 405is fixed to processing machine 400, rotation of lift bearing support 460will cause lift arm 407 to pivot about operator arm pivot axis 412,thereby moving the processing head 406. It is advantageous to considerthe gear drive shaft (or "operator arm shaft") as being fixed withrespect to operator base 405 when envisioning the operation of the liftmechanism.

Operator lift mechanism 448 is also advantageously provided with a liftovertravel protect 462 or lift switch. The lift rotate protect operatesin a manner similar to that described for the rotate overtravel protect444 described above. Turning now to FIG. 11, a left side view of theoperator arm 407 is shown which shows the lift overtravel protect indetail.

The lift overtravel protect preferably includes a lift optical switchlow 463 and a lift optical switch high 464. Other types of limitswitches can also be used. The switch high 464 and switch low 463correspond to beginning and endpoint travel of lift arm 407. The primarylift switch component is lift flag 465, which is firmly attached to leftoperator base yoke arm 421. The lift optical switches are preferablymounted to the movable operator arm 407. As operator arm 407 travels inan upward direction in pivoting about operator arm pivot axis 412, liftoptical switch high 464 will approach the lift flag 465. Should the liftmotor encoder 455 fail to stop the lift motor 454 as desired, the liftflag 465 will break the optical path of the lift optical switch high 464thus producing a signal which can be used to stop the lift motor. Inlike manner, when the operator arm 407 is being lowered by rotating itin a clockwise direction about the operator arm pivot axis 412, as shownin FIG. 11, overtravel of operator arm 407 will cause lift opticalswitch low 463 to have its optical path interrupted by lift flag 465,thus producing a signal which may be used to stop lift motor 452. As isshown in FIG. 11, lift flag 465 is mounted to left operator base yokearm 421 with slotted lift flag mounting slots 467 and removable liftflag fasteners 466. Such an arrangement allows for the lift flag to beadjusted so that the lift overtravel protect system only becomes activeafter the lift arm 407 has traveled beyond a preferred point.

Processing Head

Turning now to FIG. 6, a front elevation schematic view of theprocessing head 406 is shown. Processing head 406 is described in moredetail in FIGS. 7 and 8. Turning now to FIG. 7, a sectional view of theleft front side of processing head 406 is shown. Processing head 406advantageously includes a processing head housing 470 and frame 582.Processing head 406 is preferably round in shape in plan view allowingit to easily pivot about process head pivot axis 411 with nointerference from operator arm 407, as demonstrated in FIGS. 3-5.Returning to FIG. 7, processing head housing 470 more preferably hascircumferential grooves 471 which are formed into the side of processhead housing 470. Circumferential grooves 471 have a functional benefitof increasing heat dissipation from processing head 406.

The sides of processing head housing 470 are advantageously providedwith rotate shaft openings 474 and 475 for receiving respectively leftand right processing head pivot shafts 429 and 430. Processing headpivot shafts 429 and 430 are secured to the processing head 406 byrespective left and right processing head mounts 472 and 473. Processinghead mounts 472 and 473 are affirmative connected to processing headframe 582 which also supports processing head door 476 which is itselfsecurely fastened to processing head housing 470. Consequently,processing head pivot shafts 429 and 430 are fixed with respect toprocessing head 407 and may therefore rotate or pivot with respect tooperator arm 407. The details of how processing head pivot shafts 429and 430 are received within operator arm 407 were discussed supra.

Processing head housing 470 forms a processing head void 477 which isused to house additional processing head components such as the spinmotor, the pneumatic finger actuators, and service lines, all discussedmore fully below.

The processing head also advantageously includes a workpiece holder andfingers for holding a workpiece, as is also more fully described below.

Processing Head Spin Motor

In a large number of semiconductor manufacturing processes, is desirableto spin the semiconductor wafer or workpiece during the process, forexample to assure even distribution of applied process fluids across theface of the semiconductor wafer, or to aid drying of the wafer after awet chemistry process. It is therefore desirable to be able to rotatethe semiconductor workpiece while it is held by the processing head.

The semiconductor workpiece is held during the process by workpieceholder 478 described more fully below. In order to spin workpiece holder478 relative to processing head 406 about spin axis 479, an electric,pneumatic, or other type of spin motor or workpiece spin drive isadvantageously provided.

Turning to FIG. 8, spin motor 480 has armatures 526 which drive spinmotor shaft 483 in rotational movement to spin workpiece holder 478.Spin motor 480 is supported by bottom motor bearing 492 in bottom motorhousing 482. Bottom motor housing 482 is secured to processing head 406by door 476. Spin motor 480 is thus free to rotate relative toprocessing head housing 470 and door 476. Spin motor 480 is preferablyadditionally held in place by top motor housing 481 which rests onprocessing head door 476. Spin motor 480 is rotationally isolated fromtop motor housing 481 by top motor bearing 493, which is disposedbetween the spin motor shaft 483 and top motor housing 481.

The spin motor is preferably an electric motor which is provided with anelectrical supply source through pivot shaft 429 and/or 430. Spin motor480 will drive spin motor shaft 483 about spin axis 479.

To secure workpiece holder rotor 484 to spin motor shaft 483, workpieceholder rotor 484 is preferably provided with a rotor hub 485. Rotor hub485 defines a rotor hub recess 486 which receives a flared end ofworkpiece holder shaft 491. The flared end 487 of workpiece holder shaft491 is secured within the rotor hub recess 486 by workpiece shaftsnap-ring 488 which fits within rotor recess groove 489 above the flaredportion 487 of workpiece holder shaft 491.

The workpiece holder shaft 491 is fitted inside of spin motor shaft 483and protrudes from the top of the spin motor shaft. The top of workpieceholder shaft 491 is threaded to receive thin nut 527 (see FIG. 7). Thinnut 527 is tightened against optical tachometer 499 (describe more fullybelow). Optical tachometer 499 is securely attached to spin motor shaft483 such that as the spin motor 480 rotationally drives the spin motorshaft 483, the workpiece holder shaft 491 is also driven.

Workpiece holders may be easily changed out to accommodate variousconfigurations which may be required for the various processesencountered in manufacturing of the semiconductors. This is accomplishedby removing spin encoder 498 (described below), and then thin nut 527.Once the thin nut has been removed the workpiece holder 478 will dropaway from the processing head 406.

The processing head is also advantageously provided with a spin encoder498, more generally described as a workpiece holder encoder, and anoptical tachometer 499. As shown in FIG. 7, spin encoder 498 is mountedto top motor housing 481 by encoder support 528 so as to remainstationary with respect to the processing head 406. Optical tachometer499 is mounted on spin motor shaft 483 so as to rotate with the motor480. When operated in conjunction, the spin encoder 498 and opticaltachometer 499 allow the speed, acceleration, and precise rotationalposition of the spin motor shaft (and therefore the workpiece holder478) to be known. In this manner, and when spin motor 480 is provided asa servo motor, a high degree of control over the spin rate,acceleration, and rotational angular position of the workpiece withrespect to the process head 407 may be obtained.

In one application of the present invention the workpiece support isused to support a semiconductor workpiece in an electroplating process.To accomplish the electroplating an electric current is provided to theworkpiece through an alternate embodiment of the fingers (described morefully below). To provide electric current to the finger, conductivewires are run from the tops of the fingers inside of the workpieceholder 478 through the electrode wire holes 525 in the flared lower partof workpiece holder shaft 491. The electrode wires are provided electriccurrent from electrical lines run through processing pivot shaft 429and/or 430.

The electrical line run through pivot shaft 430/429 will by nature bestationary with respect to processing head housing 470. However, sincethe workpiece holder rotor is intended to be capable of rotation duringthe electroplating process, the wires passing into workpiece supportshaft 491 through electrode wire holes 525 may rotate with respect toprocessing head housing 470. Since the rotating electrode wires withinworkpiece shaft 491 and the stationary electrical supply lines runthrough pivot shaft 430/429 must be in electrical communication, therotational/stationary problem must be overcome. In the preferredembodiment, this is accomplished by use of electrical slip ring 494.

Electrical slip ring 494, shown in FIG. 7, has a lower wire junction 529for receiving the conductive ends of the electrical wires passing intoworkpiece holder shaft 491 by electrode wire holes 525. Lower wirejunction 529 is held in place within workpiece holder shaft 491 byinsulating cylindrical collar 497 and thus rotates with spin motor shaft483. The electrode wires terminate in a single electrical contact 531 atthe top of the lower wire junction 529. Electrical slip ring 494 furtherhas a contact pad 530 which is suspended within the top of workpieceholder shaft 491. Contact pad 530 is mechanically fastened to spinencoder 498, which, as described previously, remains stationary withrespect to processing head housing 470. The stationary-to-rotationaltransition is made at the tip of contact pad 530, which is in contactwith the rotating electrical contact 531. Contact pad 530 iselectrically conductive and is in electrical communication withelectrical contact 531. In the preferred embodiment, contact pad 530 ismade of copper-beryllium. A wire 585 carries current to fingerassemblies when current supply is needed, such as on the alternativeembodiment described below.

Processing Head Finger Actuators

Workpiece holder 478, described more fully below, advantageouslyincludes fingers for holding the workpiece W in the workpiece holder, asshown in FIGS. 7 and 8. Since the workpiece holder 478 may be removed asdescribed above, it is possible to replace one style of workpiece holderwith another. Since a variety of workpiece holders with a variety offingers for holding the workpiece is possible, it is desirable to have afinger actuator mechanism disposed within processing head 407 which iscompatible with any given finger arrangement. The invention is thereforeadvantageously provided with a finger actuator mechanism.

Turning to FIG. 7, a finger actuator mechanism 500 is shown. Fingeractuator mechanism 500 is preferably a pneumatically operated mechanism.A pneumatic cylinder is formed by a cavity 501 within top motor housing481. Pneumatic piston 502 is disposed within cavity 501. Pneumaticpiston 502 is biased in an upward position within cavity 501 by actuatorspring 505. Actuator spring 505 is confined within cavity 501 by cavityend cap 507, which is itself constrained by retaining ring 508.Pneumatic fluid is provided to the top of pneumatic piston 502 viapneumatic inlet 503. Pneumatic fluid is provided to pneumatic inlet 503by pneumatic supply line 504 which is routed through processing headpivot shaft 429 and hence through the left fork 418 of the operator arm407. Turning to FIG. 8, it can be seen that a second pneumatic cylinderwhich is identical to the pneumatic cylinder just described is alsoprovided.

Pneumatic piston 502 is attached to actuator plate 509 by actuator plateconnect screw 510. Wave springs 529 provide flexibility to theconnecting at screws 510. Actuator plate 509 is preferably an annularplate concentric with the spin motor 580 and disposed about the bottommotor housing 482, and is symmetrical about spin axis 479. Actuatorplate 509 is secured against pneumatic piston 502 by bushing 512 whichis disposed in pneumatic piston recess 511 about pneumatic piston 502.Bushing 512 acts as a support for wave springs 529 to allow a slighttilting of the actuator plate 509. Such an arrangement is beneficial forproviding equal action against the finger actuator contacts 513 aboutthe entire actuator plate or ring 509.

When pneumatic fluid is provided to the space above the pneumatic piston502, the pneumatic piston 502 travels in a downward directioncompressing actuator spring 505. As pneumatic piston 502 travelsdownward, actuator plate 509 is likewise pushed downward by flexiblebushing 512. Actuator plate 509 will contact finger actuator contacts513 causing the fingers to operate as more fully described below.

Actuator seals 506 are provided to prevent pneumatic gas from bypassingthe top of the pneumatic piston 502 and entering the area occupied byactuator spring 505.

Processing Head Workpiece Holder

Workpiece holder 478 is used to hold the workpiece W, which is typicallya semiconductor wafer, in position during the semiconductormanufacturing process.

Turning now to FIG. 8, a finger 409 is shown in cross section. Finger409 advantageously includes a finger actuator contact 513 which iscontacted by actuator plate 509, as described above. Finger actuatorcontact 513 is connected to finger actuator lever 514 (more generally,"finger extension") which is cantilevered from and connected to thefinger stem 515. Finger stem 515 is inserted into finger actuator lever514. Disposed about the portion of the finger actuator lever whichencompasses and secures finger stem 515 is finger diaphragm 519. Fingerdiaphragm 519 is preferably made of a flexible material such asTetrafluoroethylene, also known as Teflon® (registered trademark of E.I. DuPont de Nemours Company). Finger 409 is mounted to workpiece holderrotor 484 using finger diaphragm 519. Finger diaphragm 519 is insertedinto the finger opening 521 in rotor 484. The finger diaphragm 519 isinserted into the rotor from the side opposite that to which theworkpiece will be presented. Finger diaphragm 519 is secured to rotor484 against rotor diaphragm lip 523. Forces are intentionally impartedas a result of contact between the actuator plate 509 and the fingeractuator contact 513 when the finger actuator mechanism 500 is actuated.

Finger actuator lever 514 is advantageously biased in a horizontalposition by finger spring 520 which acts on finger actuator tab 522which in turn is connected to finger actuator lever 514. Finger spring520 is preferably a torsion spring secured to the workpiece holder rotor484.

Finger stem 515 is also preferably provided with finger collar or nut517 which holds the finger stem 515 against shoulder 518. Finger collar517 threads or otherwise securely fits over the lower end of fingeractuator lever 514. Below the finger collar 517, finger stem 515 extendsfor a short distance and terminates in fingertip 414. Fingertip 414contains a slight groove or notch which is beneficially shaped toreceive the edge of the workpiece W.

In actuation, finger actuator plate 509 is pushed downward by fingeractuator mechanism 500. Finger actuator plate 509 continues its downwardtravel contacting finger actuator contacts 513. As actuator plate 509continues its downward travel, finger actuator contacts are pushed in adownward direction. As a result of the downward direction, the fingeractuator levers 514 are caused to pivot.

In the preferred embodiment, a plurality of fingers are used to hold theworkpiece. In one example, six fingers were used. Once the actuatorplate 509 has traveled its full extent, the finger stems 515 will betilted away from the spin axis 479. The circumference described by thefingertips in this spread-apart position should be greater than thecircumference of the workpiece W. Once a workpiece W has been positionedproximate to the fingertips, the pneumatic pressure is relieved on thefinger actuator and the actuator spring 505 causes the pneumatic piston502 to return to the top of the cavity 501. In so doing, the actuatorplate 509 is retracted and the finger actuator levers are returned totheir initial position by virtue of finger springs 520.

Semiconductor Workpiece Holder--Electroplating Embodiment

FIG. 15 is a side elevational view of a semiconductor workpiece holder810 constructed according to a preferred aspect of the invention.

Workpiece holder 810 is used for processing a semiconductor workpiecesuch as a semiconductor wafer shown in phantom at W. One preferred typeof processing undertaken with workpiece holder 810 is a workpieceelectroplating process in which a semiconductor workpiece is held byworkpiece holder 810 and an electrical potential is applied to theworkpiece to enable plating material to be plated thereon. Such can be,and preferably is accomplished utilizing a processing enclosure orchamber which includes a bottom half or bowl 811 shown in phantom linesin FIG. 1. Bottom half 811 together with workpiece holder 810 forms asealed, protected chamber for semiconductor workpiece processing.Accordingly, preferred reactants can be introduced into the chamber forfurther processing. Another preferred aspect of workpiece holder 810 isthat such moves, rotates or otherwise spins the held workpiece duringprocessing as will be described in more detail below.

Processing Head and Processing Head Operator

Turning now to FIG. 15, semiconductor workpiece holder 810 includes aworkpiece support 812. Workpiece support 812 advantageously supports aworkpiece during processing. Workpiece support 812 includes a processinghead or spin head assembly 814. Workpiece support 812 also includes ahead operator or lift/rotate assembly 816. Spin head assembly 814 isoperatively coupled with lift/rotate assembly 816. Spin head assembly814 advantageously enables a held workpiece to be spun or moved about adefined axis during processing. Such enhances conformal coverage of thepreferred plating material over the held workpiece. Lift/rotate assembly816 advantageously lifts spin head assembly 814 out of engagement withthe bottom half 811 of the enclosure in which the preferred processingtakes place. Such lifting is preferably about an axis x₁. Once solifted, lift/rotate assembly 816 also rotates the spin head and heldworkpiece about an axis x₂ so that the workpiece can be presentedface-up and easily removed from workpiece support 812. In theillustrated and preferred embodiment, such rotation is about 180° fromthe disposition shown in FIG. 15. Advantageously, a new workpiece can befixed or otherwise attached to the workpiece holder for furtherprocessing as described in detail below.

The workpiece can be removed from or fixed to workpiece holder 810automatically by means of a robotically controlled arm. Alternatively,the workpiece can be manually removed from or fixed to workpiece holder810. Additionally, more than one workpiece holder can be provided tosupport processing of multiple semiconductor workpieces. Other means ofremoving and fixing a semiconductor workpiece are possible.

FIG. 16 is a front sectional view of the FIG. 15 semiconductor workpieceholder. As shown, workpiece support 812 includes a motor 818 which isoperatively coupled with a rotor 820. Rotor 820 is advantageouslymounted for rotation about a rotor spin axis 822 and serves as a stagingplatform upon which at least one finger assembly 824 is mounted.Preferably, more than one finger assembly is mounted on rotor 820, andeven more preferably, four or more such finger assemblies are mountedthereon and described in detail below although only two are shown inFIG. 16. The preferred finger assemblies are instrumental in fixing orotherwise holding a semiconductor workpiece on semiconductor workpieceholder 810. Each finger assembly is advantageously operatively connectedor associated with a actuator 825. The actuator is preferably apneumatic linkage which serves to assist in moving the finger assembliesbetween a disengaged position in which a workpiece may be removed fromor added to the workpiece holding, and an engaged position in which theworkpiece is fixed upon the workpiece holder for processing. Such isdescribed in more detail below.

FIG. 17 is a top or plan view of rotor 820 which is effectively takenalong line 3--3 in FIG. 16. FIG. 16 shows the preferred four fingerassemblies 824. As shown, rotor 820 is generally circular and resemblesfrom the top a spoked wheel with a nearly continuous bottom surface.Rotor 820 includes a rotor center piece 826 at the center of which liesrotor axis 822. A plurality of struts or spokes 828 are joined orconnected to rotor center 826 and extend outwardly to join with andsupport a rotor perimeter piece 830. Advantageously, four of spokes 828support respective preferred finger assemblies 824. Finger assemblies824 are advantageously positioned to engage a semiconductor workpiece,such as a wafer W which is shown in phantom lines in the position suchwould occupy during processing. When a workpiece is so engaged, it isfixedly held in place relative to the rotor so that processing can beeffected. Such processing can include exposing the workpiece toprocessing conditions which are effective to form a layer of material onone or more surfaces or potions of a wafer or other workpiece. Suchprocessing can also include moving the workpiece within a processingenvironment to enhance or improve conformal coverage of a layeringmaterial. Such processing can, and preferably does include exposing theworkpiece to processing conditions which are effective to form anelectroplated layer on or over the workpiece.

Finger Assembly

Referring now to FIGS. 18-20, various views of a preferred fingerassembly are shown. The preferred individual finger assemblies areconstructed in accordance with the description below. FIG. 18 is anisolated side sectional view of a finger assembly constructed inaccordance with a preferred aspect of the invention. FIG. 19 is a sideelevational view of the finger assembly turned 90° from the view of FIG.18. FIG. 20 is a fragmentary cross-sectional enlarged view of a fingerassembly and associated rotor structure. The finger assembly as setforth in FIGS. 18 and 19 is shown in the relative position such as itwould occupy when processing head or spin head assembly 814 (FIGS. 15and 16) is moved or rotated by head operator or lift/rotate assembly 816into a position for receiving a semiconductor workpiece. The fingerassembly is shown in FIGS. 18 and 20 in an orientation of about 180°from the position shown in FIG. 20. This typically varies because spinhead assembly 814 is rotated 180° from the position shown in FIGS. 15and 16 in order to receive a semiconductor workpiece. Accordingly,finger assemblies 824 would be so rotated. Lesser degrees of rotationare possible.

Finger assembly 824 includes a finger assembly frame 832. Preferably,finger assembly frame 832 is provided in the form of a sealed contactsleeve which includes an angled slot 832a, only a portion of which isshown in FIG. 19. Angled slot 832a advantageously enables the fingerassembly to be moved, preferably pneumatically, both longitudinally androtationally as will be explained below. Such preferred movement enablesa semiconductor workpiece to be engaged, electrically contacted, andprocessed in accordance with the invention.

Finger assembly frame 832 includes a finger assembly frame outer flange834 which, as shown in FIG. 20, engages an inner drive plate portion 836of rotor 820. Such engagement advantageously fixes or seats fingerassembly frame 832 relative to rotor 820. Such, in turn, enables thefinger assembly, or a portion thereof, to be moved relative to the rotorfor engaging the semiconductor workpiece.

Finger Assembly Drive System

Referring to FIGS. 16 and 18-20, the finger assembly includes a fingerassembly drive system which is utilized to move the finger assemblybetween engaged and disengaged positions. The finger assembly drivesystem includes a bearing 838 and a collet 840 operatively adjacent thebearing. Bearing 838 includes a bearing receptacle 839 for receiving apneumatically driven source, a fragmented portion of which is showndirectly above the receptacle in FIG. 20. The pneumatically drivensource serves to longitudinally reciprocate and rotate collet 840, andhence a preferred portion of finger assembly 824. A preferredpneumatically driven source is described below in more detail inconnection with the preferred longitudinal and rotational movementeffectuated thereby. Such longitudinal reciprocation is affected by abiasing mechanism in the form of a spring 842 which is operativelymounted between finger assembly frame 832 and a spring seat 844. Theconstruction develops a bias between finger assembly frame 832 andspring seat 844 to bias the finger into engagement against a wafer.Advantageously, the cooperation between the above mentionedpneumatically driven source as affected by the biasing mechanism of thefinger assembly drive system, enable collet 840 to be longitudinallyreciprocated in both extending and retracting modes of movement. Assuch, finger assembly 824 includes a biased portion which is biasedtoward a first position and which is movable to a second position awayfrom the first position. Other manners of longitudinally reciprocatingthe finger assembly are possible.

Finger Assembly Electrical System

Referring to FIGS. 16 and 19, the finger assembly preferably includes afinger assembly electrical system which is utilized to effectuate anelectrical bias to a held workpiece and supply electrical currentrelative thereto. The finger assembly electrical system includes a pinconnector 846 and a finger 848. Pin connector 846 advantageouslyprovides an electrical connection to a power source (not shown) via wire585 and associate slip ring mechanism, described above in connectionwith FIG. 7 and other Figs. This is for delivering an electrical biasand current to an electrode which is described below. Pin connector 846also rides within angled slot 832a thereby mechanically defining thelimits to which the finger assembly may be both longitudinally androtationally moved.

Finger 848 is advantageously fixed or secured to or within collet 840 bya nut 850 which threadably engages a distal end portion of collet 840 asshown best in FIG. 18. An anti-rotation pin 852 advantageously securesfinger 848 within collet 840 and prevents relative rotationtherebetween. Electrical current is conducted from connector 846 throughcollet 840 to finger 860, all of which are conductive, such as fromstainless steel. The finger and collet can be coated with a suitabledielectric coating 856, such as TEFLON or others. The collet 840 andfinger member 860 are in one form of the invention made hollow andtubular to conduct a purge gas therethrough.

Finger assembly 824 may also optionally include a distal tip or fingertip 854. Tip 854 may also have a purge gas passage formed therethrough.Finger tip 854 advantageously engages against a semiconductor workpiece(see FIG. 20) and assists in holding or fixing the position of theworkpiece relative to workpiece holder 810. Finger tip 854 also assistsin providing an operative electrical connection between the fingerassembly and a workpiece to which an electrical biased is to be appliedand through which current can move. Finger tip 854 can include anelectrode contact 858 for electrically contacting a surface of asemiconductor workpiece once such workpiece is secured as describebelow.

Finger Assembly Drive System Interface

A finger assembly drive system interface is operatively coupled with thefinger assembly drive system to effectuate movement of the fingerassembly between the engaged and disengaged positions. A preferredfinger assembly drive system interface is described with reference toFIGS. 16 and 20. One component of the finger assembly drive systeminterface is a finger actuator 862. Finger actuator 862 isadvantageously provided for moving the finger assembly between theengaged and disengaged position. Finger actuator 862 acts by engagingbearing receptacle 839 and moving finger assembly 824 between an engagedposition and a disengaged position. In the engaged position, finger tip854 is engaged against a semiconductor workpiece. In the disengagedposition finger tip 854 is moved away from the workpiece.

The finger assembly drive system interface includes pneumatic actuator825 (FIG. 16). Pneumatic actuators 825 are operatively connected to anactuation ring 863 and operates thereupon causing the drive plate tomove reciprocally in the vertical direction as viewed in FIG. 16. Fingeractuator 862 is operatively connected to actuation ring 863 in a mannerwhich, upon pneumatic actuation, moves the finger actuator intoengagement with bearing receptacle 839 along the dashed line in FIG. 20.Such allows or enables the finger assembly to be moved longitudinallyalong a first movement path axis 864.

Pneumatic actuator linkage 825 also includes a secondary linkage 865.Secondary linkage 865 is pneumatic as well and includes a link arm 867.Link arm 867 is connected or joined to an actuator torque ring 869.Preferably, torque ring 869 is concentric with rotor 820 (FIG. 17) andcircuitously links each of the finger actuators together. A pneumaticoperator 871 is advantageously linked with the secondary linkage 865 forapplying force and operating the linkage by angularly displacing torquering 869. This in turn rotates the finger assemblies into and away fromthe engaged position.

Preferably finger actuator engagement bits 862, under the influence ofpneumatic linkage 825, moves the finger assembly, and more specificallycollet 840 and finger 848 along a first axial movement path along axis864. The finger actuator engagement bits 862, then under the influenceof pneumatic operator 871 are turned about the axes of each bit like ascrewdriver. This moves collet 840 and finger 848 in a second angularmovement. Such second movement turns the fingers sufficiently to producethe angular displacement shown in FIG. 21. According to a preferredaspect of this invention, such movement of the finger assemblies betweenthe engaged and disengaged positions takes place when spin head assembly814 has been moved 180° from its FIG. 15 disposition into a face-upcondition.

The engagement bits 862 can be provided with a purge gas passagetherethrough. Gas is supplied via tube 893 and is passed through thefinger assemblies.

Engaged and Disengaged Positions

FIG. 21 is a view of a portion of a finger assembly, taken along line21--21 in FIG. 18. Such shows in more detail the above-described engagedand disengaged positions and movement therebetween relative to aworkpiece W In the disengaged position, finger 848 is positionedadjacent the semiconductor workpiece and the finger tip and electrodecontact do not overlap with workpiece W. In the engaged position, thefinger tip overlaps with the workpiece and the electrode is brought tobear against the workpiece. From the disengaged position, fingerassembly 824, upon the preferred actuation, is moved in a firstdirection away from the disengaged position. Preferably, such firstdirection is longitudinal and along first movement path axis 864. Suchlongitudinal movement is linear and in the direction of arrow A as shownin FIGS. 18 and 19. The movement moves the finger assembly to theposition shown in dashed lines in FIG. 18. Such movement is effectuatedby pneumatic operator 825 which operates upon actuation ring 863 (FIG.16). This in turn, causes finger actuator 862 to engage with fingerassembly 824. Such linear movement is limited by angled slot 832a.Thereafter, the finger assembly is preferably moved in a seconddirection which is different from the first direction and preferablyrotational about the first movement path axis 864. Such is illustratedin FIG. 21 where the second direction defines a generally arcuate pathbetween the engaged and disengaged positions. Such rotational movementis effectuated by secondary linkage 865 which pneumatically engages thefinger actuator to effect rotation thereof. As so moved, the fingerassembly swings into a ready position in which a semiconductor workpieceis ready to be engaged and held for processing. Once the finger assemblyis moved or swung into place overlapping a workpiece, the preferredfinger actuator is spring biased and released to bear against theworkpiece. An engaged workpiece is shown in FIG. 20 after the workpiecehas been engaged by finger tip 854 against a workpiece standoff 865, andspin head assembly 814 has been rotated back into the position shown inFIG. 15. Such preferred pneumatically assisted engagement takes placepreferably along movement path axis 864 and in a direction which is intothe plane of the page upon which FIG. 21 appears.

As shown in FIG. 18, finger 848 extends away from collet 840 andpreferably includes a bend 866 between collet 840 and finger tip 854.The preferred bend is a reverse bend of around 180° which serves topoint finger tip 854 toward workpiece W when the finger assembly ismoved toward or into the engaged position (FIG. 21). Advantageously, thecollet 840 and hence finger 848 are longitudinally reciprocally movableinto and out of the engaged position.

Finger Assembly Seal

The finger assembly preferably includes a finger assembly seal 868 whichis effectuated between finger 848 and a desired workpiece when thefinger assembly is moved into the engaged position. Preferably, adjacentfinger tip 854. A seal 868 is mounted adjacent electrode contact 858 andeffectively seals the electrode contact therewithin when finger assembly824 is moved to engage a workpiece. The seal can be made of a suitableflexible, preferably elastomeric material, such as VITON.

More specifically, and referring to FIG. 22, seal 868 can include a rimportion 870 which engages workpiece surface W and forms a sealingcontact therebetween when the finger assembly is moved to the engagedposition. Such seal advantageously isolates finger electrode 860 fromthe processing environment and materials which may plate out orotherwise be encountered therein. Seal 868 can be provided with anoptional bellows wall structure 894 (FIG. 22), that allows more axialflexibility of the seal.

FIG. 22 shows, in solid lines, seal 868 in a disengaged position inwhich rim portion 870 is not engaged with workpiece W. FIG. 22 alsoshows, in phantom lines, an engaged position in which rim portion 870 isengaged with and forms a seal relative to workpiece W. Preferably andadvantageously, electrode contact 858 is maintained in a generallyretracted position within seal 868 when the finger assembly is in thedisengaged position. However, when the finger assembly is moved into theengaged position, seal 868 and rim portion 870 thereof splay outwardlyor otherwise yieldably deform to effectively enable the electrode andhence electrode contact 858 to move into the engaged position againstthe workpiece. One factor which assists in forming the preferred sealbetween the rim portion and the workpiece is the force which isdeveloped by spring 842 which advantageously urges collet 840 and hencefinger 860 and finger tip 858 in the direction of and against thecaptured workpiece. Such developed force assists in maintaining theintegrity of the seal which is developed in the engaged position.Another factor which assists in forming the preferred seal is theyieldability or deformability of the finger tip when it is brought intocontact with the workpiece. Such factors effectively create a continuousseal about the periphery of electrode contact 858 thereby protecting itfrom any materials, such as the preferred plating materials which areused during electroplate processing.

Methods and Operation

In accordance with a preferred processing aspect of the presentinvention, and in connection with the above-described semiconductorworkpiece holder, a sheathed electrode, such as electrode 860, ispositioned against a semiconductor workpiece surface in a manner whichpermits the electrode to impart a voltage bias and current flow to theworkpiece to effectuate preferred electroplating processing of theworkpiece. Such positioning not only allows a desired electrical bias tobe imparted to a held workpiece, but also allows the workpiece itself tobe mechanically held or fixed relative to the workpiece holder. That is,finger assembly 824 provides an electrical/mechanical connection betweena workpiece and the workpiece holder as is discussed in more detailbelow.

Electrode 856 includes an electrode tip or electrode contact 858 whichengages the workpiece surface. A seal is thus formed about the peripheryof the electrode tip or contact 858 so that a desired electrical biasmay be imparted to the workpiece to enable plating material to be platedthereon. According to a preferred aspect of the processing method, theelectrode is moved in a first direction, preferably longitudinally alonga movement axis, away from a disengaged position in which the workpiecesurface is not engaged by the electrode tip or contact 858 Subsequently,the electrode is rotated about the same movement axis and toward anengaged position in which the electrode tip may engage, so as to fix,and thereafter bias the workpiece surface. Such preferred movement iseffectuated by pneumatic linkage 825 and pneumatic operator 871 asdescribed above.

According to a preferred aspect of the invention, the seal which iseffectuated between the electrode member and the workpiece is formed byutilizing a yieldable, deformable seal member 868 which includes a rimportion 870. The rim portion 870 serves by contacting the workpiecesurface to form a continuous seal as shown in FIG. 8. The preferredelectrode tip is brought into engagement with the workpiece surface byadvancing the electrode tip from a retracted position within the seal orother sheath to an unretracted position in which the workpiece surfaceis engaged thereby. Such movement of the electrode tip between theretracted and unretracted positions is advantageously accommodated bythe yieldable features of the seal 868.

In addition to providing the preferred electrical contact between theworkpiece and the electrode tip, the finger assembly also forms amechanical contact or connection between the assembly and the workpiecewhich effectively fixes the workpiece relative to the workpiece holder.Such is advantageous because one aspect of the preferred processingmethod includes rotating the workpiece about rotor axis 822 while theworkpiece is exposed to the preferred plating material. Such not onlyensures that the electrical connection and hence the electrical biasrelative to the workpiece is maintained during processing, but that themechanical fixation of the workpiece on the workpiece holder ismaintained as well.

The above described pneumatically effectuated movement of the preferredfinger assemblies between the engaged and disengaged positions is butone manner of effectuating such movement. Other manners of effectuatingsuch movement are possible.

The invention also includes novel methods for presenting a workpiece toa semiconductor process. In such methods, a workpiece is first securedto a workpiece holder. The methods work equally well for workpieceholders known in the art and for the novel workpiece holders disclosedherein.

In the next step in the sequence, the workpiece holder is rotated abouta horizontal axis from an initial or first position where the workpieceholder was provided with the workpiece to a second position. The secondposition will be at an angle to the horizontal. The angle of theworkpiece holder to the horizontal is defined by the angle between theplane of the workpiece and the horizontal. In the method, the workpieceholder is advantageously suspended about a second horizontal axis whichis parallel to the first horizontal axis of the workpiece holder. Atthis point in the method, the angle between the first and secondhorizontal axes and a horizontal plane corresponds to the angle betweenthe workpiece holder and the horizontal. The workpiece holder is thenpivoted about the second horizontal axis to move the workpiece and theworkpiece holder from its initial location to a final location in ahorizontal plane. Advantageously, when the workpiece holder is pivotedabout the second horizontal axis, the first horizontal axis also pivotsabout the second horizontal axis.

Preferably, during the step of rotating the workpiece holder about thefirst horizontal axis, the angle of the workpiece holder with respect tosome known point, which is fixed with respect to the workpiece holderduring the rotation process, is continually monitored. Monitoring allowsfor precise positioning of the workpiece holder with respect to thehorizontal surface.

Likewise, during pivoting of the workpiece holder about the secondhorizontal axis, it is preferable that the angle defined by the lineconnecting the first and second horizontal axes and the horizontal planebe continually monitored. In this manner, the absolute position of theworkpiece holder (and hence the workpiece itself) will be known withrespect to the horizontal plane. This is important since the horizontalplane typically will contain the process to which the workpiece will beexposed.

It should be noted that in the above and following description, whilethe workpiece is described as being presented to a horizontal plane, itis possible that the workpiece may also be presented to a vertical planeor a plane at any angle between the vertical and the horizontal.Typically, the processing plane will be a horizontal plane due to thedesire to avoid gravitational effects on process fluids to which theworkpiece is exposed. In one embodiment after the workpiece has beenpresented to the processing plane, the workpiece holder is rotated abouta spin axis to cause the workpiece to spin in the horizontal plane.Although not required in all semiconductor manufacturing processes, thisis a common step which may be added in the appropriate circumstance.

The next advantageous step in the method consists of pivoting theworkpiece holder about the second horizontal axis back along the paththat the workpiece holder was initially pivoted along when presentingthe workpiece to the horizontal process plane. There is no requirementthat the workpiece holder be pivoted back to the same position whence itbegan, although doing so may have certain advantages as more fullydescribed below.

The method advantageously further consists of the step of rotating theworkpiece holder about the first horizontal axis to return the workpieceto the position when it was initially presented to and engaged by theworkpiece holder. It is advantageous to rotate the workpiece holderabout the first axis in a direction opposite from the initial rotationof the workpiece holder.

The advantage of having the workpiece holder terminate at an endposition which corresponds to the initial position when the workpiecewas loaded into the workpiece holder is efficiency. That is, additionalmachine movements are not required to position the workpiece holder toreceive a new workpiece.

The method more preferably includes the step of rotating the workpieceholder about the first horizontal axis at least two support points alongthe first horizontal axis. This beneficially provides support andstability to the workpiece holder during the rotation process andsubsequent movement of the apparatus.

The method also more preferably includes the step of pivoting theworkpiece holder along with the first horizontal axis about the secondhorizontal axis at least two support points along the second horizontalaxis. This beneficially provides additional support for the workpieceholder while allowing the workpiece holder to be moved in a vertical or"Z-axis" direction.

Importantly, the only motion described in the above method is rotationalmotion about several axes. In the method described, there is notranslational motion of the workpiece holder in a X-, Y-, or Z-axiswithout corresponding movement in another axis as a result of rotatingthrough an arc.

Second Embodiment Processing Station--Generally

FIG. 23 shows principal components of a second semiconductor processingstation 900 incorporating features of the invention. Processing station900 as shown is specifically adapted and constructed to serve as anelectroplating station similar to electroplating station 400 describedhereinabove. To reduce unnecessary replication, only the principal partsshowing differences and features of the invention are shown anddescribed. Other aspects of the invention are as described above or canbe done in a variety of constructions.

The two principal parts of processing station 900 are the workpiecesupport assembly 901 and the processing bowl 917. The workpiece support401 will be considered first and the processing bowl and its featureswill be described in further detail later in this description. As FIG.23 indicates, portions of the workpiece support 401 mate with theprocessing bowl to provide a substantially closed processing vesselwhich encloses a substantially enclosed processing or manufacturingchamber 904.

Workpiece Support Generally

The workpiece support processing head holds a wafer W for rotationwithin the processing chamber 904. A rotor assembly 984 has a pluralityof workpiece-engaging fingers 979 that hold the wafer against featuresof the rotor. Fingers 979 are also preferably adapted to conduct currentbetween the wafer and a plating electrical power supply (not shown).

Workpiece Support Head Operator

The workpiece support assembly 901 includes a processing head 906 whichis supported by an head operator 907. Head operator 907 includes anupper portion 908 which is adjustable in elevation to allow heightadjustment of the processing head. Head operator 907 also has a headconnection shaft 909 which is operable to pivot about a horizontal pivotaxis 910. Pivotal action of the processing head using operator 907allows the processing head to be placed in an open or face-up position(not shown) for loading and unloading wafer W. FIG. 23 shows theprocessing head pivoted into a face-down position in preparation forprocessing.

A variety of suitable head operators which provide both elevational andhorizontal pivoting action are possible for use in this system. Thepreferred operators are also fitted with positional encoders (not shown)which indicate both the elevation of the processing head and its angularposition as pivoted about horizontal head pivot axis 910.

Workpiece Support Main Part

FIGS. 24 and 25 show additional details of the preferred construction ofprocessing head 906. The processing head includes a main part whichmoves with and is relatively stationary with respect to the pivot shaft909. The main part supports a rotating assembly which will be describedin greater detail below.

The main part includes a processing head housing 970 and processing headframe 982. The processing head frame 982 includes a door plate 983. Adoor ring member 984 is joined to plate 983 using suitable fasteners toprovide a door assembly which serve as the principal parts covering theupper opening of the processing bowl when the processing head is matedwith the bowl.

The processing head frame also includes a frame-pivot shaft connection985 which includes two mounting rings which receive and securely connectwith the processing head pivot shaft 909. FIG. 25 shows that the pivotshaft connection mounting rings are made in two parts and secured byfasteners (not shown). The pivot shaft connection base 935 is secured tothe door plate 983 using fasteners.

Processing head 906 is generally round in shape when viewed in planview. The processing head main part includes a housing 970 which has afirst housing part 971 and a second housing part or housing cap 972. Theprocessing head housing 970 encloses a main part enclosure whichsurrounds a processing head main part mechanism chamber 973. Chamber 973is used to house additional processing head components, such as the spinmotor, the finger actuators, and related service lines, such asdiscussed more fully below.

The upper surface of the door ring member 984 is provided with a groovewhich receives the lower edge of the first housing piece 971. The outerperiphery of the door ring member also advantageously includes aperipheral groove 986 which mounts an inflatable door seal 987. Seal 987seals with portions of the processing bowl to form a more fluid-tightprocessing chamber therewithin.

The lower surface of the door ring member 984 is preferably providedwith an annular rotor receiving groove 988 which receives top peripheralportions of the rotor therein in close proximity. This constructionallows a gas purge (not shown) to be applied between the door and rotorto help prevent processing vapors from migrating behind the rotor andinto to the various mechanisms present in the main part of theprocessing head. The periphery of the door ring member is furtherprovided with a chamfered lower edge to facilitate mating with theprocessing bowl.

The processing head also advantageously includes a moving assembly inthe form of a workpiece holder 978. The workpiece holder includesfingers 979 for holding a semiconductor workpiece. These features willbe more fully described below.

Workpiece Support Rotor Drive

The processing head main part also includes a workpiece holder drivewhich moves the workpiece holder relative to the main part of theprocessing head. The preferred action is for the workpiece holder driveto be in the form of a rotor drive which rotates the workpiece holder.The rotor drive can be an electric motor, pneumatic motor or othersuitable drive. As shown, the processing head includes an electricworkpiece spin motor 980.

The drive motor 980 has stator armatures 916 which drive motor shaft 918in rotational movement. Drive motor 980 is supported by bottom motorbearing 921 in bottom motor housing 922. Bottom motor housing 922 issecured to the main part of the processing head at a central opening inthe door plate 983. Motor 980 is also held in place by a top motorhousing 923. Drive motor 980 is rotationally isolated from top motorhousing 923 by a top motor bearing 927, which is disposed between thespin motor shaft 918 and the top motor housing. Both motor housings aresecured to the processing head frame 982 using fasteners 924 whichextend down through the motor housings and into the door plate 983. Thefasteners 924 also extend upwardly through frame extensions 925. Frameextensions 925 support a top frame piece 926. Cap 972 is screwed ontopiece 926 at mating threads along the lower interior portion of the cap.

The drive motor is preferably an electric motor provided with a supplyof electricity via wiring run through pivot shaft 909 or otherwiseextending to the processing head.

Workpiece Support Rotor Assembly

The hollow shaft 918 of the drive motor receives portion of a rotorassembly therein. The rotor assembly is secured to the motor shaft andis rotated therewith. FIG. 26 shows major portions of the rotor assemblyin exploded detail. The rotor assembly 930 includes a rotor shaft 931.Rotor shaft 931 has a rotor shaft hub 932 which is held within a shafthub receptacle 933 formed in an inner rotor part 934. The inner or firstrotor part 934, also called an inner rotor drive plate, has a pluralityof spokes which extend from the inner rotor part hub 935 outwardly toconnect with a peripheral band 936. The shaft hub 932 is held in the hubreceptacle 933 using a snap-ring 937.

The inner rotor part 934 also includes a plurality of receptacles 937.Receptacles 937 are used to mount a plurality of actuator transmissionassemblies 960. The transmission receptacles 937 receive lower portionsof the transmission assemblies. The receptacles have bottom openingsthrough which the finger assemblies 979 (see FIG. 24) extend and aremounted in the transmission assemblies. Additional description isprovided below in connection with the finger assembly actuators.

FIG. 26 also shows that the rotor assembly 930 preferably includes asecond or outer rotor part 940. The inner and outer rotor parts aresecured together by fasteners 941 (see FIG. 24). The outer rotor part940 includes a rotor face panel 943 which extends across the disk-shapedrotor part to form a barrier to processing fluids.

The front or exposed side of the outer rotor part is provided withapertures 787 through which finger actuator transmission shafts 963extend in supporting relationship for the fingers 979. Workpiece supportstandoffs 721 are mounted upon the face of the rotor to support the backside of the workpieces in opposition to the forces exerted by thefingers 979. The face of the rotor can also advantageously be providedwith workpiece peripheral guide pins 722 to facilitate proper locationof a wafer upon installation upon the face of the rotor.

Along the back side of the outer rotor part are reinforcing ribs 942which align with the spokes of the inner rotor part 934. The reinforcingribs 942 receive fasteners 941 and connect the two rotor parts together.At the periphery of the outer rotor part is a side wall 944. The upperor back edge of the peripheral side wall 944 is in close fittingrelationship with the door ring 984 at annular groove 988 to resistmigration of processing fluids to the back side of the rotor assembly.

The outer rotor part 940 also has an array of bosses 948 at theperipheral end of the reinforcing ribs 942. Within bosses 948 are fingerpassageways 949 which allow the finger assemblies 979 to mount in thefinger actuator transmission assemblies 960. The rotor assembly alsoincludes the transmission assemblies and finger assemblies. Additionaldetails of these components as well as additional parts of the fingeractuation mechanisms is described in greater detail below.

The rotor shaft 931 fits inside of motor shaft 918 and protrudes fromthe top of the shaft and is held by a rotor shaft mounting nut 888. Alsomounted near the top of the rotor shaft is an optical tachometer 499.Optical tachometer 499 is securely attached to motor shaft 918 andfeatures, such as notches, formed on the tachometer are opticallydetected to provide a precise measurement of rotor angular velocity. Theoptical emitter-detector couplet used with tachometer 499 are not shown,but are mounted on either sides of the wheel to allow selective passageof light therethrough.

The rotor assembly is also advantageously provided with a angularposition encoder 498. As shown, encoder 498 is mounted to the top motorhousing 923 so as to remain stationary with respect to the main part ofthe processing head. The angular position encoder 498 and opticaltachometer 499 allow the speed, acceleration, and precise rotationalposition of the motor shaft 918 and rotor assembly to be known andcontrolled.

In one application of the present invention the workpiece support isused to support a semiconductor workpiece in an electroplating process.To accomplish the electroplating an electric current is provided to theworkpiece through an alternate embodiment of the fingers (described morefully below). To provide electric current to the electrode fingers 979,conductive wires (not shown) are run from the transmissions 960 towardthe hub of the rotor. Current is supplied to the electrode fingers 979through the hollow rotor shaft using wires (not shown) connected to aslip ring electrical connector 687 mounted near the upper end of shafts918 and 931.

Workpiece Detection Subsystem

The processing head also preferably includes a wafer or workpiecedetection subsystem. This subsystem allows the processing head tothrough its control system to determine whether there is a workpieceheld in the rotor or not. This is of particular significance if thesystem experiences a power interruption or otherwise is being started inany situation where workpieces may be present in the machine.Operational safeguards can then be included in the control system toprevent mishandling of wafers or processing stations which may have aworkpiece held therein.

As shown in FIG. 25, the processing head frame part 983 is provided witha mounting 738 which is an appropriately shaped recess used to mount adetector 739. Detector 739 is preferably an optical emitter-detectorunit which emits a beam which passes downwardly as oriented in FIG. 25.The emitted beam passes through workpiece detector windows 741 (see FIG.26) formed in the face panel of the outer rotor part. The windows can bediscrete inserts, or more preferably, they are thinly dimensioned panelportions of the rotor face panel 943. The rotor face panel isadvantageously made of a material which is transmissive of the detectorbeam being used. For example, the panel can be made from polyvinylidenefluoride polymer which is thinned to a suitably thin dimension, such asin the approximate range from about 1-5 millimeters.

A suitable detector 739 is a Sunx brand model RX-LS200, and othercommercially available detectors. The preferred detector uses aninfrared beam emitter (not individually shown) which is detected by apair of beam detectors (not individually shown). The beam emitter andbeam detectors are preferably part of the same unit which serves as theworkpiece detector. The workpiece detector preferably operated in atrigonometric mode. In the trigonometric mode, the angle of thereflected beam is an important discriminating parameter. Thus anyportion of the beam reflected by the detector window 741 is incidentupon the pair of detectors at a reflection angle which is outside of thenormal detection angel range. Such portions of the beam reflected by thewindow 741 are thus minimized and the detector is not triggered by suchreflectance. Instead, the pair of beam detectors are adjusted to sense areflected beam which is incident at a reflected angle associated withthe wafer or other workpiece surface which is more distant than thewindow. When there is no workpiece held in the workpiece holder, thenthe detector senses the absence and this is used by the control systemas an indication that there is no wafer present in the wafer support.

In general the emitted infrared beam used in the preferred workpiecedetector subsystem is sufficient to detect the presence of a wafer orother semiconductor workpiece held in a stationary position with therotor positioned so that one of the windows 741 is in position alignedto allow the emitted beam to pass therethrough and be reflected by theworkpiece back through the window for detection. The detection systemdescribed herein is not sufficient to allow detection during rotation ofthe rotor and any workpiece held thereon. The invention may also bepracticed in a situation where sensing can be accomplished while therotor rotates.

The workpiece detector arrangement shown has the distinct benefit ofbeing mounted wholly behind the rotor face panel without provision ofany openings which might allow processing fluids to enter the spacebehind the rotor. This reduces maintenance, improves reliability, andsimplifies construction costs.

Workpiece Support Finger Actuator

The preferred wafer support also includes a plurality of wafer-engagingfingers 979 positioned about the periphery of the wafer or otherworkpiece. FIG. 27 shows the front face of the outer rotor part 940 in aface-up orientation with fingers 979 extending therefrom. The preferredfingers are J-shaped and mounted for pivotal action about a finger pivotaxes 953. The pivotal action preferably ranges between an outboardposition and an inboard position. In the outboard position the J-shapedfingers are positioned outwardly and clear of the wafer peripheral edge.A preferred outboard position is illustrated in FIG. 27. In the outboardposition the hooked portions of the J-shaped fingers are oriented atapproximately 15 angular degrees outward from a line drawn tangent tothe periphery of the wafer adjacent to the finger. In the inboardposition the fingers are positioned inwardly to engage the wafer, asshown in FIG. 28. In the inboard position the hooked portions of theJ-shaped fingers are oriented at approximately 45 angular degrees inwardfrom a line drawn tangent to the periphery of the wafer adjacent to thefinger.

The face of the rotor assembly is provided with workpiece standoffsupports 721 which are in complementary position to the engagement endsof the fingers when the fingers are in a retracted position to hold thewafer. This construction securely captures the wafer or other workpiecebetween the fingers and the standoffs.

In addition to the pivotal action of the engagement fingers, the fingersare also move axially toward and away from the face of the rotor. In theinboard position the fingers are retracted toward the wafer to engagethe exposed, front face of the wafer along a marginal band adjacent tothe periphery of the wafer. In the outboard position the fingers areextended away from the face of the wafer to prevent rubbing action asthe fingers pivot away from the wafer. This compound action includingboth a pivot component and an axial component is accomplished using afinger actuator transmission 960 shown in perspective relationship tothe rotor in FIG. 26. Transmissions 960 are mounted within thetransmission receptacles 937 of the inner rotor part 934. Thetransmissions are further mounted by transmission retainers 951 whichare secured by fasteners to inner rotor part 934.

FIG. 29 shows the finger actuator transmission 960 in greater detail.The lower end of transmission 960 includes a finger head mountingreceptacle 954. Receptacle 954 is advantageously provided with a lockingfeature included to secure the fingers in the receptacles. As shown, thereceptacle includes a convoluted, bayonet-type, locking pin groove 955.Locking pin groove 955 receives a transversely mounted finger mountingpin 956 (see FIG. 32) which is a rolled or other suitable pin secured inthe head of the finger assembly.

FIGS. 29, 30, and 31 detail the preferred construction of the actuatortransmissions 960. The transmissions include a transmission base 961which is provided with a mounting cutout 962 which is borne upon by theretainers 951 when installed in the rotor. The base also includes acentral passageway within which is received a transmission shaft 963.Shaft 963 can both pivot and move axially within the central passageway.The shaft and base 961 are constructed to interact in a manner whichcontrols the relative motion of the shaft. This is done to provide thecompound pivotal and axial movement of the shaft and a finger 979 whichis held therein. As shown, the inactive mechanism is provided in theform of a shaft channel or groove 964 which is engaged by a shaftcamming control member 965. The camming action of the groove is provideby a helical advance over a pivotal movement range of approximately 60degrees of rotation. The associate axial travel is in the range ofapproximately 5-20 millimeters, more preferably about 10-15 millimeters.

The camming control member 965 is advantageously in the form of a ball966 held into the groove 964 using a ball support fastener 967. Fastener967 has a ball socket which receives portions of the ball. Fastener 967also serves as a convenient electrical contact terminal when electricityis supplied to the fingers 979.

The shaft 963 is provided with an interior shaft passageway 968 whichreceives a spring retainer 969. Spring retainer 969 has an engagementhead which mechanically engages with a finger mounting spring 938. Thespring 938 serves to bias a finger assembly into a locked position usingthe locking pin 956 held in biased relationship by groove 955. Springretainer 969 is secured in the passageway by a set screw 939.

FIG. 31 also shows that the transmission 960 preferably includes atransmission head 656. Transmission head 656 is connected to the upperend of shaft 963 using a bearing 657 which allows the shaft to pivotrelative to the head pieces 658 and 659. Head pieces 658 and 659 capturethe bearing between them, and are joined by head fasteners 660. The headfasteners 660 thread into a pair of head guide rods 661. Head guide rods661 are slidably received by two guide passageways 662 formed in thetransmission base 961. The head assembly is biased upwardly by two headbias springs 664. Engagement between ball 966 and groove 964 limits theupward movement of the head assembly under action by springs 664.

The lower end of shaft 963 is sealed to the base 961 using a shaft seal667 which helps to keep any abraded metal within the transmission andprevent contamination toward the fingers 979. Shaft 963 also has atransverse hole 665 which is used as an electrical connection featurethat receives a wire (not shown) run from the slip ring down the rotorshaft. The wire is secured in hole 665 by a set screw (not shown).

The transmissions 960 are activated by a transmission head depressionring 683 (see FIG. 24). Depression ring 683 is connected to an operatoroutput connection ring 684 (see FIG. 25). The operator output connectionring is secured by fasteners to the output shafts of pneumatic actuatorengines 691. FIG. 25 also shows pneumatic manifolds 692 used to supplythe actuator engines. The preferred construction shows three actuatorengines 691 which have outputs which move upwardly and downwardly todepress the transmission heads 658 and operate the fingers in thecompound axial and pivotal motion already described. The actuator engineoutputs are extended to depress rings 683 and 684, and to depress thetransmission heads 658 thus causing the fingers 979 to move from theinboard retracted positions of FIG. 28 to the outboard extendedpositions of FIG. 27.

Electrode Fingers With Submerged Conductive Current Transfer Areas

FIGS. 32-39 show a number of different electrode finger constructions.The different constructions shown have particular application todiffering applications. FIG. 32 shows a finger assembly 631 havingintended application for contacting a semiconductor wafer during blanketplating of copper. Finger assembly 631 includes a finger shaft 632 whichis formed in a J-shape and made from an electrically conductivematerial, such as stainless steel or tungsten. The finger assembly alsopreferably includes an integral finger head 633 which is received intothe receptacle 954 of the actuator transmission 960. The head has a pinaperture which receives the locking pin 956 therein for engagement withthe locking groove 955 formed in the receptacle of the actuatortransmission.

Finger assembly 631 also preferably includes dielectric sheathing 634and 635. Dielectric sheathing 634 and 635 is advantageously made from apolyvinylidene fluoride coating or layer applied to the shaft of thefinger. The dielectric sheathing is preferably provided upon onlylimited portions of the electrode shaft and adjacent the contact head636. The contact head has a contact face 637 which directly bears uponthe wafer to pass electrical current between the electrode and wafer.The contact face 637 is approximately equal to a fluid submersionboundary 639. The submersion boundary indicates the approximate level ofthe plating liquid during processing.

The limited coverage of the dielectric sheathing is for the purpose ofimproving the uniformity of plating performed upon semiconductorworkpieces held in the wafer support. It is believed that thesubmersible surfaces of the electrode finger are best provided withdielectric sheathing segments which comprise between approximately 25percent and 75 percent of the submersible area of the electrode. Theseamounts do not consider the contact face as part of the areas. FIG. 32show two segments 634 and 635 which cover about 50 percent of theelectrode finger shaft exterior surfaces from the submersion line 639downward, as positioned in a plating liquid bath during processing. Thefirst dielectric segment 634 is adjacent to the contact face 637. afirst electrically conductive segment 642 exists between the dielectricsegment 634 and the contact face 637. A second electrically conductivesegment 643 exists between first and second dielectric segments 634 and635. A third electrically conductive segment 644 exists between thesecond dielectric segment 635 and submersion line 639. The electricallyconductive segments 642-644 provide current transfer areas which causeplating current that is supplied through the finger head 633 to bedirectly passed to the plating liquid contained in a plating bath. Thisis believed to provide a more uniform current density and more uniformvoltage profile across the surface of a wafer which is being blanketplated with copper or other plating metals.

FIG. 33 shows another plating system workpiece support electrode 651having many of the same features as electrode 631 described immediatelyabove. The same reference numerals have been used to designate similarparts. Differences between finger electrodes 651 and 631 will now bedescribed. Electrode 651 has three current transfer areas 642-644. Thesize and shape of areas 642-644 are somewhat different from thecorresponding areas of electrode 631. More specifically, the second andthird current transfer areas 643 and 644 are elongated along the shaft.The second dielectric sheath segment 635 is shortened. A thirddielectric segment 653 has been included. The third dielectric sheath654 forms the submerged dielectric segment 653 and also extends abovethe submersion line 639 to head 633. The area of the submerged currenttransfer segments is between 25 and 75 percent of the submerged surfacearea, more particularly, about 50 percent.

Electrode 651 is also provided with a distal contact insert part 655.Insert part 655 is received within an insert receptacle 616 formed inthe distal end of the electrode shaft. The insert contact tip 655defines a contact face 617 which bears upon a wafer being held. Theinsert contact part is made from a conductive material which ispreferably non-corrosive material, such as platinum or stainless steel.

FIG. 34 shows a further electrode finger construction in the form ofelectrode finger 979. Similar parts to electrode fingers 631 and 651 aresimilarly numbered in this figure. The electrode shaft is covered by adielectric sheath 621 which largely covers the electrode shaft andleaves only a first current conductive area 642 which is immediatelyadjacent to the contact face 637. This construction is contrasted to theelectrodes 631 and 651 because electrode finger 979 does not havecurrent transfer areas which comprise 25 percent of the submergedportion of the electrode. It also does not have current transfer areaswhich are exposed in a manner which is separated by a dielectric segmentinterpositioned between the contact face 637 and the removed or remotecurrent conductive segment.

FIG. 35 shows a further electrode finger 601 which has submerged currenttransfer areas 642-644. It also has dielectric segments 634 and 635.Dielectric segment 635 of this figure has a differing shape and coveragearea as compared to the other electrodes discussed above. In thisconstruction the dielectric sheath extends along the outer curvature ofthe electrode J-bend. Curved upper edges extend so as to provide anoverlying web portion 603 which covers the inner curvature of theJ-bend. Performance in terms of plating uniformity has been found to besuperior in some processes which employed the electrode of this figure.

The electrodes 631, 651 and 601 are preferably used in novel processesaccording to this invention. These processes include contacting asurface of the semiconductor article or workpiece with an electrode at acontact face thereof. The methods also include submersing a portion orportions of the electrode into a plating bath containing a platingliquid which is typically a solution and mixture have various componentsknown in the art. The methods also preferably include wetting aprocessed surface of the semiconductor article with the plating bath.Further included is the step of moving or conducting electrical currentthrough the electrode and plating bath to perform an electroplatingaction to occur upon at least the processed surface of the wafer orother article. The methods further advantageously include diverting aportion of the electrical current directly between the electrode and theplating bath along at least one electrically conductive segment of theelectrode. The electrically conductive segment is preferably spaced fromthe contact face a substantial distance, such as greater than 5millimeters, and preferably is spaced therefrom by an interveningdielectric sheath.

Electrode Fingers With Dielectric Sheaths Covering Submerged Areas

FIG. 36 shows another electrode finger 681 which is similar to electrodefinger 651. Finger 681 is similar to finger 651 except it includes afull dielectric sheath 682 which extends from above submersion line 639to contact insert side walls 619. This construction preferably uses acoating layer 682, such as from polyvinylidene fluoride, which can beapplied by dipping or otherwise forming the layer over the shaft of theelectrode. This construction includes the dielectric layer over thedistal end of the electrode shaft and into sealing relationship with theside walls of the insert contact part or tip 655. The dielectric coatingor other layer 682 excludes corrosive processing fluids. Since thecontact tip is preferably made from a non-corrosive material, such asplatinum, the only material of the electrode which is exposed to directcorrosive action is the non-corrosive tip which is able to maintain goodservice despite the difficult operating environment.

Additionally, the construction of electrode 681 is particularlyadvantageous because the joint formed between the inserted contact tip655 and receptacle 616 is covered and protected from direct exposure tothe corrosive plating liquid and fumes present in the processingchamber.

The invention further includes methods for plating metals onto thesurface of a semiconductor workpiece using electrode finger 681. Themethods include contacting a surface of the workpiece with an electrodeassembly using a contact face, such as face 617, on a contact part, suchas contact insert part 655. The contact insert is mounted on the distalend of the electrode shaft. It is further preferably provided with adielectric layer formed about the distal end in sealing relationshipagainst the contact part. The methods further preferably includesubmersing or otherwise wetting a processed surface of the workpiece,such as in a plating bath liquid used to plate the workpiece with aplating material. The methods also preferably include excluding theplating bath liquified from the contact part joint, such as the jointformed between the contact part 655 and receptacle 616. The methodsfurther include electroplating the workpiece with plating material bypassing electrical current through the contact part and between thesemiconductor workpiece and electrode assembly. The contact face platinglayer is more preferably formed from the plating material as isdescribed below in additional detail. The method is most preferably usedto plate copper onto the surface of semiconductor materials, such assilicon or oxides thereof.

Pre-Conditioning of Electrode Contact Faces

FIGS. 37 and 38 illustrates a further electrode construction inaccordance with further inventive aspects of the workpiece supportsystems and methods described herein. FIG. 37 shows distal end portionsof an electrode 614. Electrode 614 is otherwise similar to electrode 681described above. At the distal end of electrode finger 614 is a distalexposed surface 615 is made from a suitable material, such as stainlesssteel or tungsten. A dielectric sheath 616 is advantageously providedalong the exterior portions of the electrode adjacent to the distalexposed surface 615.

FIG. 38 shows the electrode 614 with a deposited contact face platinglayer 618 formed thereon. The layer 618 is preferably a layer made fromthe same or a very similar material as is being plated onto thesemiconductor workpieces with which electrode 614 is to be used. Forexample, if copper is being plated onto the semiconductor device, thenthe layer 618 is a layer plated from the same plating bath or from aplating bath which will provide a layer 618 which is the same or verysimilar to the constituency of the copper deposited onto thesemiconductor device being plated. In a preferred manner of carrying outthis invention, the exposed distal surfaces 615 are placed into aplating bath and electrical current is conducted through the bath anddistal end of the electrode 614. This causes a plating action to occurwhich deposits the layer 618. The resulting layer is preferably at least1 micron in thickness, more preferably in the approximate range of 1-100microns thick.

This method and resulting construction results in a pre-conditionedelectrode contact surface which is of the same or very similar materialas plated onto the semiconductor device during the later platingoperation. The use of the same or similar materials prevents galvanic orother types of chemical reactions from developing due to dissimilarityof the metals involved.

The invention further includes additional methods for plating metalsonto the surface of a semiconductor workpiece. The preferred methodsinclude contacting a surface of the semiconductor workpiece with anelectrode at a contact face forming a part of the electrode. The contactface is covered or substantially covered by a contact face platinglayer. The contact face plating layer is formed from a contact faceplating material which is the same or chemically similar to thee platingmaterial which is to be plated onto the semiconductor workpiece duringprocessing. The methods also preferably include submersing or otherwisewetting a processed surface of the workpiece into a plating bath orusing a plating liquid or fluid. Other means for depositing the platingmaterial as a contact face layer may alternatively be used. The methodsfurther include electroplating workpiece plating material onto thesemiconductor workpiece by passing electrical current between theworkpiece and the electrode having such contact face plating layer. Themethods are of particular advantage in the plating of copper ontosemiconductors using a copper contact face plating layer.

Methods Using Workpiece-Engaging Electrode Assembly With Sealing Boot

FIG. 39 shows a further electrode finger 583 which has features similarto 651 and such similar features are identified with the same referencenumbers. Electrode finger 583 differs from finger 651 in that theelectrode shaft 584 is covered between the head 633 to the distal end ofthe electrode shaft with a cover or boot 585. Boot 585 is preferablymade in a manner which provides a continuous cover from near theelectrode head 633 to a distal contact lip 586. The boot includesadditional features adjacent the contact insert part 655. Morespecifically, the boot includes a skirt portion 587 which extends abovethe electrode shaft distal end surface 588. The contact face 617 of theinsert part 655 is preferably about even with the distal contact lip 586which is formed upon the end of the skirt portion 587. The skirt portionserves as a deformable seal which comes into contact with a surface of awafer or other semiconductor workpiece being contacted.

FIGS. 40 and 41 illustrate novel methods which advantageously utilizethe improved features of electrode finger 583. The methods involveplating metals onto the surface of semiconductor workpieces,specifically onto a semiconductor wafer W which has a substrate or othersubjacent layer 561 which has been previously provided with a thinmetallic seed layer 562 which is shown by a heavy black line in thatfigure. A via or other opening 563 exists in a photoresist layer 564which overlies the substrate and seed layers.

FIG. 40 shows the electrode 583 poised in a disengaged position inpreparation for contact with the surface. FIG. 41 shows the electrode583 retracted against the surface of the workpiece. In the engagedposition the contact face 617 is extended through the opening 563 andinto direct electrical contact with exposed areas of the seed layer 562which are not covered by the layer of photoresist or other coveringlayer. A seal is formed by depressing the skirt 587 and attached lip 586against the outer surface of the photoresist layer 564.

The novel methods include selecting an electrode assembly having desiredfeatures, such the features of electrode finger 583. More specifically,the selecting step preferably includes selecting an electrode assemblyhaving an electrode contact which is surrounded by an electrode boot orother sealing member. The methods also include engaging coated surfaceportions, such as photoresist layer 564, with the sealing member orboot. The sealing can occur about a continuous peripheral sealing line,such as defined by the engagement of lip 586 against the photoresistsurface. It is important to engage the lip against the photoresistsurface and not against the seed layer 562 because sealing against theseed layer can cause erosive or corrosive effects to occur at or nearthe line or area of engagement of the boot with the seed layer. Sucherosive or corrosive actions can cause the seed layer to becomediscontinuous or even totally isolated. A discontinuous or isolatedcontact region will lead to electroplating failure because the neededcurrent will not be communicated in an even manner to the areas adjacentto the electrode which need current to accomplish plating. Theengagement of the seal against the coating causes a sealed space to beenclosed within the seal by the electrode boot and the processed surfaceof the workpiece.

The novel methods further include enclosing a via or other openingwithin the seal. The via is present on the processed surface and hasassociated exposed seed layer portions therein for allowing electricalcontact to be made. The via is needed to allow direct contact betweenthe contact face of the electrode finger assembly and the seed layerwhich is used to communicate electrical current across the wafer forelectroplating a metal thereonto. Thus, the methods further includecontacting the seed layer through the via with the electrode contact toform an electrically conductive connection between the electrodeassembly and the seed layer. This contacting step is advantageouslyperformed using a contact face which bears upon the seed layer and isenclosed with the sealed space. Other desirable attributes explainedhereinabove in connection with other electrodes can also be utilized toadvantage in performing this process.

The methods still further include wetting the processed surface of theworkpiece with a plating or other processing liquid. This is typicallydone by lowering the wafer holder into position to bring the outer,processed surface of the wafer into direct contact with a plating liquidheld in a plating bath, such as described elsewhere herein in additionaldetail.

The methods also preferably include passing electrical current throughthe electrode and plating bath to cause electroplating to occur uponexposed seed layer areas of the processed surface. Such exposed seedlayer areas may be trenches, vias or other features where thephotoresist layer 564 is not present to cover the seed layer 562. Theelectrical current causes electroplating to occur on such exposed seedlayer areas.

Still further, the methods preferably include excluding plating or otherprocessing liquid from the sealed space to substantially reduce oreliminate plating or other action in the area immediate adjacent to thecontact with the electrode.

The methods described above are of particular relevance to platingcopper onto semiconductors.

Plating Bowl Assembly

FIG. 42 shows an electroplating bowl assembly 303. The process bowlassembly consists of a process bowl or plating vessel 316 having anouter bowl side wall 617, bowl bottom 319, and bowl rim assembly 314.The process bowl is preferably circular in horizontal cross-section andgenerally cylindrical in shape although other shapes of process bowl maybe possible.

The invention further advantageously includes a cup assembly 320 whichis disposed within process bowl vessel 316. Cup assembly 320 includes afluid cup portion 321 having a cup side 322 and a cup bottom 323. Aswith the outer process bowl, the fluid cup 321 is preferably circular inhorizontal cross-section and cylindrical in shape. The cup assembly alsohas a depending skirt 371 which extends below the cup bottom 323 and hasflutes 372 open therethrough for fluid communication and release of anygas that might collect as the chamber below fills with liquid. The cupassembly can be made using upper and lower portions which coupletogether at a cup main joint 387. The cup is preferably made frompolypropylene or other suitable material, which is advantageouslydielectric.

The lower opening in the cup bottom wall is connected to a riser tube361 which is adjustable in height relative thereto by a threadedconnection. The riser tube seals between the bottom wall 319 of theprocess bowl and the cup bottom 323. The riser tube is preferably madefrom polypropylene or other suitable dielectric material. A fitting 362connects the riser tube 361 and the fluid inlet line 325 to allowadjustment of the anode vertical position. The fitting 362 canaccommodate height adjustment of both the riser tube and inlet line 325.The inlet line is made from a conductive material, such as titanium andis used to conduct electrical current to the anode 324, as well assupply fluid to the cup.

Process fluid is provided to the cup through fluid inlet line 325. Thefluid inlet line rises through riser tube 361 and bowl bottom opening327 and through cup fluid inlet openings 324. Plating fluid fills thecup portion 321 through opening 324 as supplied by a plating fluid pump(not shown) or other suitable supply which provides the fluid under atleast some pressure for delivery.

The upper edge of the cup side wall 322 forms a weir which determinesthe level of plating liquid within the cup. Excess fluid pours over thistop edge surface into the overflow chamber 345. The fluid held in theoverflow chamber 345 is sensed by two level detectors 351 and 352. Onelevel detector is used to sense a desired high level and the other isused to sense an overfull condition. The level of liquid is preferablymaintained within a desired range for stability of operation. This canbe done using several different outflow configurations. A preferredconfiguration is to sense the high level using detector 351 and thendrain fluid through a drain line as controlled by a control valve. It isalso possible to use a standpipe arrangement (not illustrate), and suchis used as a final overflow protection device in the preferred platingstation 303. More complex level controls are also possible.

The outflow liquid from chamber 345 is preferably returned to a suitablereservoir. The liquid can then be treated with additional platingchemicals or other constituents of the plating or other process liquidand used again.

The plating bowl assembly 303 further includes an anode 334. In thepreferred uses according to this invention, the anode is a consumableanode used in connection with the plating of copper or other metals ontosemiconductor materials. The specific anode will vary depending upon themetal being plated and other specifics of the plating liquid being used.A number of different consumable anodes which are commercially availablemay be used as anode 334.

FIG. 42 also shows a diffusion plate 375 provide above the anode 334 forrendering the fluid plating bath above the diffusion plate with lessturbulence. Fluid passages are provided over all or a portion of thediffusion plate to allow fluid communication therethrough. The height ofthe diffusion plate is adjustable using three diffuser height adjustmentmechanisms 386 and secured by three mounting fasteners 389.

Plating Anode Shield

The invention also includes an anode shield 393 which can be secured tothe consumable anode 334 using anode shield fasteners 394. The anodeshield and anode shield fasteners are preferably made from a dielectricmaterial, such as polyvinylidene fluoride or polypropylene. The anodeshield is advantageously about 2-5 millimeters thick, more preferablyabout 3 millimeters thick.

The anode shield serves to electrically isolate and physically protectthe back side of the anode. It also reduces the consumption of organicplating liquid additives consumed. Although the exact mechanism may notbe known at this time, the anode shield is believed to preventdisruption of certain materials which develop over time on the back sideof the anode. If the anode is left unshielded the organic chemicalplating additives are consumed at a significantly greater rate. With theshield in place these additive are consumed less. The shield ispreferably positioned on the anode so as to shield it from directimpingement by the incoming plating liquid.

The invention thus also include methods for plating which include othermethod steps described herein in combination with shielding a consumableanode from direct flow of plating liquids using a dielectric anodeshield.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

We claim:
 1. A semiconductor workpiece holder for use in a semiconductorelectroplating apparatus used to plate a metal or metals onto asemiconductor workpiece, comprising:a workpiece support mounted tosupport a semiconductor workpiece in position with at least a processedsurface of the workpiece being in contact with a plating bath; at leastone electrode finger which is electrically conductive and capable ofreceiving and conducting electrical current therethrough; said at leastone electrode finger having an electrode shaft which extends toward adistal end; a contact part mounted to the distal end of the electrodeshaft to provide an electrical contact face which bears upon thesemiconductor workpiece during processing to communicate electricalcurrent therethrough.
 2. A semiconductor workpiece holder according toclaim 1 wherein said contact part is made from a corrosion resistantmetal.
 3. A semiconductor workpiece holder according to claim 1 whereinsaid contact part is made from platinum.
 4. A semiconductor workpieceholder according to claim 1 wherein said electrode shaft is made from astainless steel or titanium.
 5. A semiconductor workpiece holderaccording to claim 1 wherein:said contact part is made from platinum;said electrode shaft is made from a stainless steel or titanium.
 6. Asemiconductor workpiece holder according to claim 1 and furthercomprising a dielectric layer formed about at least the distal end ofthe electrode shaft and forming a seal against side walls of the contactpart to exclude plating liquid from a joint formed between the electrodeshaft and the contact part.
 7. A semiconductor workpiece holderaccording to claim 1 and further comprising a dielectric layer formedfrom a dielectric plastic material about at least the distal end of theelectrode shaft and forming a seal against side walls of the contactpart to exclude plating liquid from a joint formed between the electrodeshaft and the contact part.
 8. A semiconductor workpiece holderaccording to claim 1 and further comprising a dielectric layer formedfrom polyvinylidene fluoride about at least the distal end of theelectrode shaft and forming a seal against side walls of the contactpart to exclude plating liquid from a joint formed between the electrodeshaft and the contact part.
 9. A semiconductor workpiece holderaccording to claim 1 and further comprising a dielectric layer coatedabout at least the distal end of the electrode shaft and forming a sealagainst side walls of the contact part to exclude plating liquid from ajoint formed between the electrode shaft and the contact part.
 10. Asemiconductor workpiece holder for use in a semiconductor electroplatingapparatus used to plate a copper material onto a semiconductorworkpiece, comprising:a workpiece support mounted to support asemiconductor workpiece in position with at least a processed surface ofthe workpiece being in contact with a plating bath; at least oneelectrode finger which is electrically conductive and capable ofreceiving and conducting electrical current therethrough; said at leastone electrode finger having an electrode shaft which extends toward adistal end; a contact part mounted to the distal end of the electrodeshaft to provide an electrical contact face which bears upon thesemiconductor workpiece during processing to communicate electricalcurrent therethrough.
 11. A semiconductor workpiece holder according toclaim 10 wherein said contact part is made from a corrosion resistantmetal.
 12. A semiconductor workpiece holder according to claim 10wherein said contact part is made from platinum.
 13. A semiconductorworkpiece holder according to claim 10 and further comprising adielectric layer formed about the distal end of the electrode shaft andforming a seal against side walls of the contact part to exclude platingliquid from a joint formed between the electrode shaft and the contactpart.
 14. A semiconductor workpiece holder according to claim 10 andfurther comprising a dielectric layer formed from a dielectric plasticmaterial about the distal end of the electrode shaft and forming a sealagainst side walls of the contact part to exclude plating liquid from ajoint formed between the electrode shaft and the contact part.
 15. Asemiconductor workpiece holder according to claim 10 and furthercomprising a dielectric layer formed from polyvinylidene fluoride aboutthe distal end of the electrode shaft and forming a seal against sidewalls of the contact part to exclude plating liquid from a joint formedbetween the electrode shaft and the contact part.
 16. A semiconductorworkpiece holder according to claim 10 and further comprising adielectric layer coated about the distal end of the electrode shaft andforming a seal against side walls of the contact part to exclude platingliquid from a joint formed between the electrode shaft and the contactpart.
 17. A semiconductor workpiece holder for use in a semiconductorelectroplating apparatus used to plate a metal or metals onto asemiconductor workpiece, comprising:a workpiece support mounted tosupport a semiconductor workpiece in position with at least a processedsurface of the workpiece being in contact with a plating bath; at leastone electrode finger which is electrically conductive and capable ofreceiving and conducting electrical current therethrough; said at leastone electrode finger having an electrode shaft which extends toward adistal end; a contact part mounted to the distal end of the electrodeshaft to provide an electrical contact face which bears upon thesemiconductor workpiece during processing to communicate electricalcurrent therethrough; a dielectric layer formed about at least thedistal end of the electrode shaft and against the contact part toexclude plating liquid from a joint formed between the electrode shaftand the contact part.
 18. A semiconductor workpiece holder according toclaim 17 wherein said contact part is made from a corrosion resistantmetal.
 19. A semiconductor workpiece holder according to claim 17wherein said contact part is made from platinum.
 20. A semiconductorworkpiece holder according to claim 17 wherein said electrode shaft ismade from a stainless steel or titanium.
 21. A semiconductor workpieceholder according to claim 17 wherein:said contact part is made fromplatinum; said electrode shaft is made from a stainless steel ortitanium.
 22. A semiconductor workpiece holder for use in asemiconductor electroplating apparatus used to plate a metal or metalsonto a semiconductor workpiece, comprising:a workpiece support mountedto support a semiconductor workpiece in position with at least aprocessed surface of the workpiece being in contact with a plating bath;at least one electrode finger which is electrically conductive andcapable of receiving and conducting electrical current therethrough;said at least one electrode finger having an electrode shaft whichextends toward a distal end; a contact part mounted to the distal end ofthe electrode shaft to provide an electrical contact face which bearsupon the semiconductor workpiece during processing to communicateelectrical current therethrough; means forming a dielectric coveringabout at least the distal end of the electrode shaft and against thecontact part to exclude plating liquid from a joint formed between theelectrode shaft and the contact part.
 23. A method for plating a metalonto the surface of a semiconductor workpiece, comprising:contacting asurface of the semiconductor workpiece with an electrode assembly; saidcontacting being performed using a contact face formed upon a contactpart, said contact part being mounted to a distal end of an electrodeshaft at a contact part joint existing between the electrode shaft andthe contact part; said electrode assembly further having a dielectriclayer formed about the distal end of the electrode shaft and in sealingrelationship against the contact part; submersing a processed surface ofthe semiconductor workpiece into a plating bath liquid which is used toplate a metal onto the processed surface of the semiconductor workpiece;excluding plating bath liquid from the contact part joint using saiddielectric layer; electroplating a metal onto the semiconductorworkpiece by passing electrical current through the contact part andbetween the semiconductor workpiece and the electrode assembly.
 24. Amethod according to claim 23 wherein said contact part is made from anoncorrosive metal.
 25. A method according to claim 23 wherein saidcontact part is made from platinum.
 26. A method for plating copper ontothe surface of a semiconductor workpiece, comprising:contacting asurface of the semiconductor workpiece with an electrode assembly; saidcontacting being performed using a contact face formed upon a contactpart, said contact part being mounted to a distal end of an electrodeshaft at a contact part joint existing between the electrode shaft andthe contact part; said electrode assembly further having a dielectriclayer formed about the distal end of the electrode shaft and in sealingrelationship against the contact part; submersing a processed surface ofthe semiconductor workpiece into a plating bath liquid which is used toplate copper onto the processed surface of the semiconductor workpiece;excluding plating bath liquid from the contact part joint using saiddielectric layer; electroplating copper onto the semiconductor workpieceby passing electrical current through the contact part and between thesemiconductor workpiece and the electrode assembly.
 27. A methodaccording to claim 26 wherein said contact part is made from anoncorrosive metal.
 28. A method according to claim 26 wherein saidcontact part is made from platinum.